When Chef is in the pharmacy, the door in the background is open in one shot, magically closed in the next, and then open again!
Mark was the drummer in "Cat Orgy," not Jonesy.
The overhead shot of Skyler after he and his band win the Battle of the Bands shows the curtains drawn wrong.
When Chef tells the doctor and pharmacist about the kids going to see Phil Collins in concert, the same voice comes out of both men.