During the scene where Rogan is accusing the Indian mall worker of being the streaker as he massages lotion into a high school chick, you notice as they are going back and forth saying "f*** you" there is a woman pushing a stroller in the right background by the kiosk who disappears and reappears while they are cursing at each other.
When Ronnie is cornered by the crack heads, the actor playing the second-to-last man he strikes with the baton changes between shots. In one shot, he is an African-American in a gray shirt. In the shot in which he is struck, he is clearly a Caucasian wearing the same clothes with gray hair and facial hair.
When Ronnie is doing his monologue in the background when he's looking at himself in the mirror (right after the bench press scene), it is obvious there is a different person looking into the bogus mirror because his body movements are not consistent with his reflection.
When Ronnie takes Brandy out to eat, he offers her his medication, when he holds it out the bottle is first shown upside down, then when the camera angle changes to show him taking them the bottle is now right side up.