Why is that a reason to cheer up? When I think about it, I’m miserable most of the time—and knowing that life was even worse for most people throughout history only makes me feel sadder.
Adopt absurdism. Nothing really matters and it's grotesquely hilarious at the same time. That might cheer you up. Occasionally.
Recently I heard Neil Degrasse Tyson saying that people came up with averages more recently than with calculus. It's not something people find relevant naturally.
Whoa now. That may be true within a strict scope of the "arithmetic mean" definition of "average", however, the idea of average as a 'concept' is much older. As an easy example, early references to agrarian yields (crop farming and how much food they produce) talk about average size of crop harvests, etc. Early tablets from Mesopotamia talk about average yield size, and those are dated 700ish BC.