When Pearl, Mr. Krabs, Squidward, Plankton, Gary, and Mrs. Puff are standing in Spongebob's bedroom at the end of "Sleepy Time", Pearl isn't wearing her nightcap. In the next shot, she is.
When Plankton wakes up, we see that he isn't wearing clothes. But when he's standing on SpongeBob's bed, he's wearing a nightshirt.
A refrigerator left open for an extended period of time would leave a house warmer, not cooler.
There's a hill where the Chum Bucket should be.
Gary and Pearl were among those annoyed at SpongeBob for appearing in their dreams, but SpongeBob didn't do anything in their dreams that ruined or inconvenienced them in any way.
When Sandy says that she doesn't understand Patrick, she says "Patrick, sometimes I just don't understund you," instead of "Patrick, sometimes I just don't understand you,".