Revealing mistake: When Hook attacks Mr. Gold, if you watch as he pushes Emma out of the way, you can easily see that one who actually pushes Jennifer Morrison is Colin O'Donoghue's stunt double. When Hook pushes Mr. Gold against the security gate, it is the stunt double who pushes Robert Carlyle. (00:18:25)
Continuity mistake: After Mary Margaret opens the birthday present from Johanna, the wrapping, lying around the present, changes position a couple of times. (00:03:55)
Continuity mistake: When David is making breakfast, he turns around, with a frying pan full of pancakes in his hands. In the next shot, he begins to lift up a pancake with a spatula, but when it cuts, he's already holding it out. (00:03:15)
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.