A man or boy who thinks he is so smart but is really a big nerd who knows nearly nothing. He is usually made fun of because he loves space movies, war, chess, and is usually a republican. You can point them out of a crowd because they will be the ones in line to get a "Mr. Know-it-all" shirt.
"Hey did you see that guy in the Mr. Know-it-all shirt?"
"No, where is he?"
"He is right there."
"Oh my gosh! He is such a nerd!"
"Yeah, what a giglet! Hah hah hah!"
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.