Continuity mistake: Andy just locked his friends out of the Zed Mart. In the overhead shot the cleaver is in the middle of the doormat section, while in the close-up it's across the two sections of the floor. (01:16:30)
Continuity mistake: Andy returns home a little early and opens the door finding mom doing tonsil hockey with a dude named Shane. The multicolored wrapping in her hand switches instantly from right to left hand as she realises her kid is there. (00:09:20)
Continuity mistake: On top of the ladder, the Xmas lights wrapped around Shane change between shots repeatedly. (00:38:00)
Answer: According to IMDb, the supervisor is basically chewing him out for being lazy and sleeping on the job, and then fires him.
TedStixon