When Alex gives his dad the coffee, his dad comments on how hot it is. Yet there is a close-up of the cup, and not the slightest trace of steam is coming out of it. [Steam is produced not from excessive heat, but from a large contrast in the coffee and the surrounding air temperature. If the temperature in the room were 80 degrees, which is feasible, and the coffee temperature were 95 degrees, then there would not be any steam coming off of the coffee, even though Alex's dad considers it "hot".]

Every time somebody climbs to the attic in the "lake house", you see a small, dark, enclosed chamber with some abandoned stuff. However, as soon as you see the "lake house" from the outside, it is a single-level construction entirely made of glass, with no inside staircase or ladder, and three smaller glasshouses on the roof. There is not a single wooden panel to enclose the attic, nor any construction in the house that looks like it could be that attic. [There are two places on the roof of the house that could contain an attic. The attic seen is very small, and there are two raised areas on the roof, one on each side of the tree.]

When Bullock's character is warning Reaves' character of the coming winter blizzard, she is looking through pictures that depicted her and her friends enjoying the snow. She then turns to the dog and asks "Do you remember that?" as well as some other statement about the dogs dislike of the snow. However when the snow happens in Reaves' time- 2004- the dog is with him. Later on they reveal that both characters have the same dog. How could the dog be in two places at one time in the year 2004 when we see when Reeves gives the dog to Bullock's boyfriend, so there is no possible way that the dog could spend time with Reeves and Bullock during the same year. [During that scene, she never implies that the dog was with her at that time, she knows she was alive then, because she already knows how old the dog is. So she was asking the dog if she remembers the snow, not because she was with her, but because she would have been alive at that time. And she was, at the lake house with Alex.]

When Sandra Bullock's 2006 boyfriend tells her he's landed a job and is moving to town, he tells her he'll be working for a company as an "in house counsel," but shortly thereafter we see him in a storefront "Attorney at Law" office. [When we see him at the store front, it is in late 2004, this is when Alex moves out of the house, and gives him the keys, so Kate and Morgan can have the lake house. At some point after that he moves away, then comes back in 2006, this is when he has the in house counsel job.]

When Alex finds his dog at Morgan and Kate's house, his girlfriend comes running up and says "Thank God you found him." The dog is a female and she surely knew that. [Most people in North America refer to all dogs as "he" and all cats as "she", especially at time of emotional stress. Logically we know that it's about a 50/50 chance, but usually a dog in literature is referred to in masculine terms.]

In the scene where Kate is sitting at a bar, another woman (Dr.) comes in and sits on her left, but in the next shot she is on Kate's right. [They were showing a shot from the mirror behind the bar.]

In the scene where Kate is at the plaza with her mum she mentions how hot the weather is for Valentines Day. 100 degrees on Valentines day." However, when we see Alex hit by the car he is wearing a thick winter coat. Why would he be wearing that on such a hot day? [She never says it's one hundred degrees, she says it's sixty degrees. Just because it's warm for Valentine's day, doesn't mean it's too warm for a winter coat. That's a character decision, not a movie mistake. It's not even Alex wearing the coat, since he's not the one who got hit by the car.]

Jack the dog appears from nowhere early in the movie and is taken in by Alex. In the future, Kate, who has not yet met Alex, owns Jack and mentions her name in a letter sent to Alex. Since at that point in the film their paths had not crossed in either present or future, where did the dog's name come from? For that matter, where did the DOG come from? [The dog was just a stray. Chronologically, Alex names him Jack after he realizes it's the same dog Kate has. Kate called the dog Jack because that's what the dog answered to at the time Kate began caring for it, having been called "Jack" by Alex. It's circuitous.]

The reason Sandra Bullock buys the lake house is because she witnesses Keanu Reeves death. She "meets" Keanu Reeves because she bought the lake house. In order for this to happen, Keanu has to die in her time, yet at the end of the movie, he lives therefore she never would have bought the house or met him. [By the time Kate witnessed Alex's death at the Plaza not only had she and Morgan already bought the Lake House, they'd already moved OUT. (She left the note for the 'new' tenant first THEN saw Alex die.) Kate had already met Alex two years earlier at her birthday party (at her old house - at this point Alex is still living at the Lake House), and the only reason she and Morgan were able to move in to the Lake House was because Alex moved out and gave Morgan the keys because he knew it was what Kate wanted. Kate's buying the LH was nothing to do with Alex's fate.]

When Sandra Bullock is lying on her bed writing to Keanu Reeves halfway through the movie, she says she likes to read to Jack (her female dog). Keanu Reeves asks what "he" (the dog) likes to listen to, even though Keanu should know the dog is a "she" because he used to own her. [He didn't know that it was his dog yet. He didn't know her name either, so when she said her dog "Jack," he assumed that it was a male.]