Continuity mistake: When Jesse reminds Walter that he flunked him, he is holding a bottle of beer that is raised to his stomach. When the shot cuts, the beer bottle is lowered away from his stomach. (00:33:20)
4 Days Out - S2-E9
Continuity mistake: When Walter is in the bathroom and repeatedly punches the towel holder at the end of the episode, you can see from the reflection of the towel holder that his glasses stand straight, but in the next shot they are slightly lowered. (00:46:20)
Continuity mistake: When Juan walks into the bar, he sets his hat flat on the bar counter. But in later shots, the hat is sitting on the edge of the bar railing. Most noticeable when he and Tortuga leave the bar.
...and the Bag's in the River - S1-E3
Character mistake: When Walt and Gretchen are talking about the elements in the body, they list hydrogen, oxygen, carbon, nitrogen, calcium, iron, sodium, and phosphorus. The percentage is short and she says "supposedly that's everything." But they don't count elements like sulfur (which has a greater abundance than sodium), potassium, chlorine, and magnesium. Even as college students, they would know those elements are in the body.
Factual error: Jesse's home number is (505) 148-3369. However, US phone numbers can't have an exchange that starts with 1. (00:14:30)
Cancer Man - S1-E4
Factual error: Walt places a squeegee on the battery of a car to blow it up. This car is a BMW e36, which has the battery in the trunk.
Continuity mistake: When Gus walks towards the nursing home towards the end of the episode, two flags in the background stop waving, but in the next shot they suddenly wave again.
Visible crew/equipment: When Combo is watching a black car parked in front of him while he was dealing as the episode started (a few moments before he's killed), a stage light can be seen reflected in his sunglasses.
Negro Y Azul - S2-E7
Continuity mistake: At the start, the writing on the blackboard changes style. Note the "CH3". (00:04:30)
Continuity mistake: When Walt breaks the news that Gray Matter is broke, Skyler's hands are on her stomach, we then see her hands are by her mouth. (00:38:50)
Continuity mistake: When Walt walks into the house at the start we can see the kitchen has a window and it's bright sunshine coming through. However, a few minutes later we see the kitchen behind Walt and it's in complete darkness despite the previously mentioned window. (00:04:50)
Continuity mistake: Just before Lucy finds Walt, the items she has gathered swap from her left arm to her right. (00:03:20)
Continuity mistake: When Jr. is walking out of Hollie's room with the freshly printed posters, the box is on the floor with the flap open by the leg of the table. When we see Jr. leaving from the box's POV, the box has rotated and the table leg can no longer be seen by the flap of the box. (00:14:20)
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm