Continuity mistake: When JB dreams about singing "Master Exploder" in the small bar, he points at one guy in the audience and literally blows his mind. When he starts pointing you can not only see JB's face, but also how his elbow is in a slight angle. In the next shot the camera shows the guy JB is pointing at and his elbow is completely stretched. The views change several times and the angle of his elbow changes after every cut, until the guy's brain is finally blown out.
Continuity mistake: When JB is in Hollywood for the first time and the guy plays Bach, you can see two Goths walk past and in the next shot the same guys walk past again.
Open Mic Host: We've got one spot left. You guys got any new material?
JB: What we got's gonna turn your brain into shit.
Truck Stop Waitress: What'll you have?
KG: What do you recommend?
Truck Stop Waitress: I recommend you order some food.