There's an incredibly good visual gag in episode 6 of Bee and Puppycat involving face masks that made me laugh uproariously for about four seconds and then start sobbing.
They say estrogen HRT makes crying easier, but I'm not sure how much of it was hormonal and how much of it was from the payoff on an earlier setup (that I had sort of predicted but which panned out so much funnier than I expected)!
I've laughed until I've had tears in my eyes before, but this was different. An overwhelming emotional release entirely stemming from an extremely well-executed joke. I had to pause the show to take out my contacts and wash my face just to deal with it, and as I stood in front of the mirror contemplating my shiny tear-stained cheeks and doing some soul-searching, I really couldn't identify any negative emotions.
Pure weird catharsis.