Expression used to insult someone's intelligence or personality.
Fun Dip is a candy found in US/Canada. It is unique in the fact that it requires two separate candies to be combined in order to properly enjoy it's intended mode of consumption. First, a tasteless sugar stick must be licked, then it must be dipped into one of three included packets of flavored sugar powder. If you remove the three packets, you are left with the tasteless sugar sticks, making the product incomplete, worthless, and bland. Therefore, describing someone as 'three packets short of a Fun Dip' means they are (a) missing general intelligence or (b) lacking flavor (in the personal sense).
I would nevervote for (POLITICIAN)! That (GENDER IDENTITY) is three packets short of a Fun Dip!
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.