Continuity mistake: Joey is standing at the mic giving insults to Frank and Dean and he's standing there with his arms folded across his chest. The camera angle changes and his hands are now in his pockets.
Continuity mistake: When they are on stage you see Sammy standing next to Joey having a conversation. The camera angle changes and Joey is now standing by himself and Sammy is on the other side of the stage with Peter.
Continuity mistake: When Sammy and May are arguing at the party, Sammy is seen looking down at the ground when the camera angle is from the front, and when the camera angle is from the back he's seen looking straight at her. Happens twice during the scene.