A lot of entrepreneurs seem obsessed with creating their life's work, their magnum opus, and leave behind some sort of legacy.

Sounds like a noble and purposeful thing to do. And, mostly, I think people find purpose within that, for lack of other things.

As I perceive it, the idea of legacy is incredibly dumb.

Who cares what people are going to think of you a hundred, a thousand years from now?

Who cares if you make the history books?

It's not like you'll be there to gloat about it.

People live their lives through the eyes of others. They validate themselves through what others think of them.

As such, their life energy is spent trying to do something cool so that they can hope that other people who don't even exist yet are going to think that they are  (were) the shit.

I much prefer the idea of doing things so that you personally think you're the shit right now.