Continuity mistake: In the scene where Joel, is driving from his house (where he just asked his wife about the filthy pool) to Step's, house (at about 59:14 - 59:17 into the film), Joel's face is not beat up or bruised at all. His face is beat up before and after this scene.
Continuity mistake: When Joel and Dean sit at the booth to talk, Dean places two beers on the table such that the labels are facing the camera. As they talk and the camera switches back and forth between the two friends, Dean's beer switches orientation showing the label in some shots and not in others, despite the fact that he does not touch the bottle whatsoever. There isn't enough time between shots to allow him to move the bottle or drink any as the bottle remains full.