Positive Nihilism.
On a long enough timeline, nothing on the scale of any given individual objectively matters. You, me, and everyone else just aren’t important enough to be bothered with. That goes both ways, though. Sure, people will almost instantly forget our daily triumphs, but they are just as likely to forget our failures. You know that urge to hide for a few days after you think someone is waving at you and you wave back, but they’re actually waving at someone behind you? They probably forget that in under an hour. The things that embarrass you are too mundane to remember. Your failures are too boring to tally.
Nothing matters so you might as well enjoy it.