It's a Wonderful Afterlife - S4.E28

Yes, you've guessed it: Beetlejuice has an off day and wishes he had never met any of his friends. Clarence Sale shows up and shows him what the Neitherworld--and the real world--would be like without him. Seeing Lydia miserable and friendless convinces BJ to change his mind, and Clarence is rewarded for his trouble with a shiny new car.