After performing ATM on someone, during which you've pulled out a plum, their teeth become fouled with said plum they become angry and sad and in a horrific grimace have a shocking resemblance to a jack-o-lantern.
My third grumpy pumpkin was with Angela. That bitch was already missing a tooth so it didn't take much to go full pumpkin.
While our lifespan is the number of years we will live, our healthspan is the number of healthy years we will have and our sexspan is is the number of years we will continue to be healthy enough to continue having an active sex life.
A lighthearted reaction upon receiving disappointing news of some sort. Usually something that isn't a particularly a big deal, esp. when it primarily affects someone else - sort of a mild schadenfreude. Sometimes doubled or tripled, and possibly said in a sing-songy voice for added comedic effect to imitate a muted trumpet, which is how the meme originated.
You didn't get any napkins with your takeout pork fried rice? Womp womp.