Plot hole: Lucy has been painting pictures of Henry since she moved into the institute. But she passes him at the zoo and doesn't recognize him.
50 First Dates (2004)
1 plot hole - chronological order
Directed by: Peter Segal
Starring: Adam Sandler, Drew Barrymore, Sean Astin, Rob Schneider
Continuity mistake: The dark roots of Lucy's hair can be seen off and on throughout the movie. One day she will have dark roots, and the next day she won't.
Henry: Ula! Get back to cleaning the pool! And if that's one of your special brownies, don't let any of the dolphins eat that.
Ula: How do you think I get the dolphins to do double-flips and play with the white kids?
Trivia: When Henry (Adam Sandler) is at the golf course with Ula and his kids, everyone except Henry is teeing off in the same style as Happy Gilmore (also played by Sandler) in "Happy Gilmore" (1996). When Henry sees this, he replies, "That is the dumbest thing I have ever seen."
Question: What would happen if Lucy stayed up all night and she was with Henry? Would she all of a sudden forget him or would it happen very slowly?
Chosen answer: Apparently, she loses all her daily memories when she enters a full sleep, so keeping her awake would have given them a chance to see each other for longer periods.
Joshua Skains
Then my question is what about the naps during the day that she takes?
Naps would reset her brain like any other sleep.