In one slightly infamous Jimmy Olsen comic, Jimmy lands in hot water with Lucy Lane when a set of incredible coincidences convince her that he's been striking her repeatedly. What finally changes her mind is when Jimmy saves her life by slapping her to keep her from screaming and startling a deadly snake.
The Batman mini-series The Legend of the Batman had an interesting one: Bats was running himself ragged trying to figure out who was trying to kill him from within. Turned out it was himself, suffering from dementia after being caught in an explosion. When he was trapped in a closing chasm of the Batcave, who should come out but his father, dressed in the "first" Batman costume, urging Bruce to keep living. Bats snaps out of it just in time to save each other. He then thanks the man behind the mask, Robin.
In a story called "The Man who Ended Batman's Career" (from Detective Comics #247), a mad scientist invents a serum that makes Batman terrified of bats in a way that even looking at himself in costume or holding a batarang freaks him out. This causes him to give up his identity as Batman and adopt the new identity of Starman (which makes him wear a hilariously crazy costume◊). The criminals eventually realize that Starman (who fights like Batman and hangs out with Robin) is Batman and use his phobia of bats to their advantage. Eventually, Robin has enough and ties him to a chair, forcing him to watch every single news-reel clip of Batman saving the day. It works.
A flashback in Y: The Last Man includes a rather profane verbal one from a flight attendant named Beth to a shell-shocked survivor at Air Traffic Control moments after everything with a Y chromosome dropped dead (including the pilot and co-pilot of Beth's plane).
Beth: Listen to me, you dumb cunt! You will pull yourself together and help me land this plane, or me and the dozens of women I'm carrying will kick the shit out of you in Hell. [beat] Air Traffic Controller: What's your current altitude, Flight 229?
In one SpongeBob SquarePants comic, SpongeBob was having a nervous breakdown over the Krusty Krab being closed down. In response, Patrick slapped himself repeatedly. Surprisingly, it had the same affect as any other time. Squidward said they were both idiots.