Continuity mistake: When Charlie, Donald, and his girlfriend have breakfast Donald puts a pot of coffee on the table. In the next shot the pot has moved to a different place, and the coffee is sloshing around in the pot. Then Donald reaches for the pot, obviously to pour coffee for his girlfriend and himself, and after a brief shot at Charlie the pot is put down and almost empty, but the content is absolutely still. Then the camera cuts briefly to Charlie, then back to Donald, and the pot is fuller and the coffee is again slightly moving.
Continuity mistake: Amelia's bangs change back and forth between shots in almost all her scenes: When she talks to Charlie at the party sitting on the floor, when he drops her off after the concert, and also when she comes to another party with her new boyfriend and meets Donald and Charlie.