In The Martian, Matt Damon used his own crap to fertilise potatoes and survive the Red Planet. While we all know Matt Damon isn't actually an astronaut, we do know that human excrement is very much real -- and it could be integral to getting real humans to Mars in the near future.
There's no feeling more rewarding than being the smartest person in the room. Sure, your friends might think it's annoying. But just imagine the sheer joy of going to the bar, hearing what drink they ordered, and explaining it to them. Try doing it on a date!