2020 is perhaps not the best year to think about things that are highly contagious, but at least that list wouldn't contain 100% bad things.
I mean, yawns get passed around a room like gravy at Thanksgiving and they're not necessarily something that you need to worry too much about. And I'm fairly certain that a good chunk of the young female population came down with a serious case of Uggs in the mid-2000s that didn't hurt anyone.
But there's just nothing quite like a smile for things that are contagious in the best way possible. So, here's to those who just want to make the world smile. They're doing good work!