Revealing mistake: When Emma opens the door of Any Given Sundae in the 2011 flashback, you can see the backdrop curtain used to insert the Storybrooke main street, thanks to its shadow in the middle of the road and a few folds reflecting the light.
Continuity mistake: The flashback scene where The Snow Queen takes Emma's video camera away from Kevin differs from what is seen on the video recording of that moment in "Breaking Glass" and "Family Business." For example, in the recording, Ingrid says, "We respect property in this house, Emma." In the actual scene, she says, "We respect property in this household, don't we, Kevin?"
Revealing mistake: When Mary Margaret and Regina engage in a sword fight in the sheriff's office, in several wide shots, the faces of Ginnifer Goodwin and Lana Parrilla's stunt doubles are visible. For example, in the wide shot where Regina is bending Mary Margaret across the desk and David says, "Careful", Lana Parrilla's stunt double is seen. (00:30:20)
Chosen answer: Even if one can see the future, it can be somewhat vague and left open to interpretation.
raywest ★
He can sees the future all jumbled up. It is like a puzzle, it is hard to put together, but even when he does put it together it is not set in stone the future can change.