Human beings don't want to just enjoy something by themselves. They want to share that emotion - they want everyone around them to enjoy it like they enjoy it or hate it like they hate it. That's what makes a video spread.
“There's never going to be a decathlon that you're going to have 10 events that your satisfied with. You're always, always going to be dissatisfied in something, and that always draws you back to try to retry that the next time you do a decathlon. It's like you go for the perfect 10.”