Continuity mistake: Emma has a flower tattoo on her left wrist. Throughout the series, there are subtle changes in its design, and its position on her arm. For example, when Emma is sitting at the table with Mary Margaret in "The Thing You Love Most", the tattoo has six petals, and is located about an inch below her hand. When she's on the phone with Ruby in "Red-Handed", the tattoo is much bigger, and the petals are arranged differently; it has also moved further up her arm, and is almost touching her hand. When she's arrested in "Tallahassee", there are five petals instead of six, the petals have a rounder shape (in "Red-Handed", they were rather pointy), and the tip of one of the petals is touching her hand. When she pulls her hair behind her ears at the tavern in "Snow Drifts", said petal is thinner, and is no longer touching her hand. When she touches Hook's face in the diner in "Birth", the tattoo has moved about a centimeter down her wrist, and the petals have a brownish color, but in previous episodes, the petals have no color. When she touches Hook's face in the Middlemist Field in the next scene, the color is gone.
Continuity mistake: The exterior shots of the buildings located across the street from Granny's Diner do not match the view seen through the front door, from inside the diner. The most obvious example is the building next to Storybrooke Country Bread, on the opposite side of the street. In the exterior shots, on the left side of the bakery, there is a blue wooden building (this can be seen, for example, when Emma is walking Henry to school in "The Thing You Love Most"), with a huge gap of approximately ten meters between the two buildings. In the interior shots where the front door of Granny's Diner is open, the view is drastically different looking: For example, when Regina enters the diner to confront Mary Margaret in "The Shepherd", when Emma brings Henry to the diner in "Welcome to Storybrooke", when Zelena enters the diner in "It's Not Easy Being Green" and when Emma comes into Granny's Diner to ask Hook out in "The Apprentice", the characters open the front door, and now there is a completely different building next to Storybrooke Country Bread. The new building seen through the doorway is made of bricks and has a completely different color, and there is no longer any gap between the two buildings; they are touching each other. Also, in some episodes, like "The Shepherd" and "7:15 AM", in the scenes inside the diner, you can see a grey wall on top of Storybrooke Country Bread. In exterior shots, there is no such wall.
Continuity mistake: The blade on the Dark One's Dagger has one side with the name of the Dark One inscribed, while the other side is decorated with a pattern. Throughout the entire series, the name keeps switching from one side of the blade to the other. In some scenes, the writing is right side up when the dagger is held in the left hand and facing the wielder, with the first letter of the Dark One's name next to the hilt: This happens, for example, when Rumplestiltskin finds the dagger in "Desperate Souls", when Mr. Gold gives the knife to August in "The Return", when Gold summons the wraith in "Broken", when Cora has the dagger in "The Miller's Daughter", when Zelena controls Mr. Gold in "The Tower", when Gold triumphantly shows the dagger to Zelena in "Kansas", when Belle controls Mr. Gold with the dagger in "Heroes and Villains", when Emma summons the first Dark One in "Nimue", when Mr. Gold shows Emma the new version of the dagger in "Swan Song" and when Weaver is holding the dagger at the Hyperion Height police station in "Eloise Gardener." In other scenes, the characters are right side up when the dagger is facing the wielder and held in the right hand, with the first letter near the tip of the blade: For example, when Rumplestiltskin summons Zoso in "Desperate Souls", when Cora steals the knife in "The Queen Is Dead", when Gold uses the dagger in "Going Home", when Regina picks it up in "Kansas", when Gold hides the dagger in "Snow Drifts", when Gold opens the sorcerer's hat box in "A Tale of Two Sisters", when the dagger is lying on the stone in Emma's basement at the end of "Nimue", when the potion is poured onto the blade in "Strange Case" and during the ritual in the cave in "The Guardian."
Continuity mistake: The headstones and statues around Regina's heart vault change dramatically throughout the series. For example, when Emma and Graham find the vault in "The Heart is a Lonely Hunter", there are two headstones on the left hand side of the vault, which are parallel to the side of the vault, and a statue of a woman on the right hand side. When Mary Margaret and David are standing outside the vault in "The Queen Is Dead", there are two completely different headstones on the left hand side, which are perpendicular to the side of the vault. There is also a cross-shaped headstone there, which wasn't there before, and an angel statue, which appeared on the left hand side of the vault when Regina went there in "The Doctor", is gone. When Regina is inside the vault with Mr. Gold in "Welcome to Storybrooke", in the establishing shot, two headstones with a cross engraved on them can be seen near the vault, but these headstones were not there in previous episodes. When Regina goes to the heart vault with a disguised Peter Pan in "The New Neverland", the statues are gone, and there are hardly any headstones around the vault at all. When Emma leaves the vault in "Breaking Glass", the statue on the right reappears, but there are no headstones in front of the vault; however, when Regina is locked inside the vault in "Shattered Sight", there are several headstones in front of it, and the angel statue on the left is back.
Continuity mistake: The location of Regina's heart vault changes throughout the series. For example, when Emma and Graham find the vault in "The Heart of the Lonely Hunter", when Regina and a disguised Peter Pan go to the vault in "The New Neverland", and when Regina hides Zelena's pendant in "Kansas", there is a slope on the left hand side of the building, but when Mary Margaret and David are standing at Johanna's grave in "The Queen Is Dead", when the green smoke goes out of the vault in "Kansas", when Regina is inside the vault with Henry in "The Apprentice", and when Regina is trapped inside the vault in "Shattered Sight", the terrain on the left hand side is flat. The trees around the vault also differ between these scenes.
Continuity mistake: When The Evil Queen crashes Snow White's wedding, the guests alternate between looking at the queen and averting their gaze between shots. (00:02:30)
Continuity mistake: When Regina casts aside the guards at Snow White's wedding, one of the guards drops his sword on the floor. In the following overhead shots, the sword has vanished. This is best seen when she turns around after saying "I shall destroy your happiness, even if it's the last thing I do." (00:02:45)
Continuity mistake: When Emma arrives at the restaurant, as the elevator opens, a waiter walks past. In the next shot, the waiter walks past the elevator again. (00:04:55)
Continuity mistake: When Emma meets up with Ryan at the restaurant, as he says, "Well, it is the Internet", Ryan is positioned next to Emma and moves to walk around her. In the next shot, he is already standing behind her as he pulls out Emma's chair. (00:05:15)
Continuity mistake: When Henry is in Emma's apartment, the amount of juice in the bottle repeatedly goes up and down between shots. (00:08:40)
Continuity mistake: In the scene where Snow is in Emma's nursery room, trying to convince Charming to talk to Rumplestiltskin, the shots have been flipped. The easiest way to spot this is Charming's scar, which is on the wrong side of his face. (00:10:30)
Continuity mistake: When Emma is driving through downtown Storybrooke, in some shots, the real-life businesses in Steveston Village (the Canadian town which doubles as the town of Storybrooke on Once Upon a Time) have not yet been transformed into Storybrooke businesses. For example, a sign on a building on the left side of the road (in the first shot) says Pacific Net and Twine, and on the other side of the street (in the shot where Henry is heard saying, "Forty-four, not-telling-you street"), the name on the local bakery, which is Romania Country Bread, and is sitting next to two businesses called Kaido and Splash. In "The Thing You Love Most", the buildings have been transformed into the Storybrooke businesses seen throughout the rest of the series: For example, Pacific Net and Twine has become Atlantic Twine and Net, the bakery has been renamed Storybrooke Country Bread, and Kaido and Splash have become Standard Clocks and Neighbor's, respectively. Also, in "The Heart is a Lonely Hunter", when Graham first meets the wolf, as the wolf walks away from him, in the background, the name "Pacific Twine and Net" appears on a window pane. (00:15:40)
Continuity mistake: When Emma arrives in town, two Storybrooke businesses, Standard Clocks and its neighbour, Modern Fashions, can be seen in a shot though a window. In the shot from above where Emma's car slows down, the name on Standard Clocks is Kaido (a real-life business in Steveston, the Canadian town which doubles as the town of Storybrooke), and there is now a white sign on Modern Fashions, which wasn't there in the first shot. (00:15:45)
Continuity mistake: When Henry and Emma arrive at Storybrooke and Archie Hopper comes over, Archie's scarf alternates between both ends hanging down his shoulders, and one end lying on top of his shoulder/neck. (00:15:55)
Continuity mistake: The way the baby blanket is wrapped around the infant Emma repeatedly changes between shots. For example, as Charming approaches the magical wardrobe, the blanket has just a tiny opening over the baby's face, and the embroidery with Emma's name on it is showing; in the next shot, the opening is much bigger, and the embroidery can no longer be seen. (00:30:00)
Continuity mistake: At the end of the episode, the hands on the clock tower move forward for the first time. In the wide shots, the circle surrounding the clock, as well as the wooden beams forming the outer edges of the area around the clock face, are white. In the close-up where the minute hand moves, the circle and edges are brown. Also, in the wide shots, the area around the clock face of the building is shaped like a square, but in the close-up, it is in the shape of a trapezoid. The same thing happens when the clock moves in "The Thing You Love Most", "A Land Without Magic" and "Darkness on the Edge of Town." (00:41:25)
Continuity mistake: Emma Swan has a flower tattoo on her left wrist. It can be glimpsed during her date with Ryan, and is visible when she's sitting at the table with Mary Margaret in "The Thing You Love Most", and when she's on the phone with Ruby in "Red-Handed." However, when she opens the door for Henry in "Pilot", the tattoo is gone. The same thing happens when she unlocks the door to her room at the inn in "The Thing You Love Most" (in the scene where she is evicted), and when she's pressing a pack of ice against her wound in "The Heart is a Lonely Hunter."
The Thing You Love Most - S1-E2
Continuity mistake: When Emma arrives in Storybrooke in "Pilot", the sign on the clock tower is a green house-shaped structure, and there are six small boarded up windows on The Tower. They are still there when Henry is watching the town clock from his window in the evening at the end of "Pilot", and in the beginning of this episode. However, the following morning, the sign on the clock tower is a white rectangular sign, and white signs are covering the windows. The clock tower remains this way for the rest of the series, with two exceptions: When Regina looks out the window and sees the purple cloud approaching in "A Land Without Magic", and when the Shadow flies through town after being released in "The New Neverland", the green plaque and the windows can be seen on the clock tower. (00:00:40 - 00:01:15)
The Thing You Love Most - S1-E2
Continuity mistake: When Emma and Henry are walking down the street, the clock face on the clock tower is on the right hand side of the library sign. In the episode's opening scene, and in every other episode, the clock face is directly above the sign. (00:01:15 - 00:13:10)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.