In the opening scene, Cliff and Norm fail to be able to talk to two females. Cliff is wearing his red mail jacket without the patch that reads 'letter carrier'. When the show returns after the first commercial break, Cliff's jacket now has the 'letter carrier' patch on it.
After Coach leaves Diane's apartment with Katherine, Sam turn the lights out by flipping the switch down. Both switches, however, are already in the down position.