My current theory is that humans have lots of desire when they are young, and as they age they lose all their desire. In my 50s I don't really have a lot of desire. I have enough to program gossip, to get pissed off about innocent children being killed or about people lying to the public. But irrespective of the outcome I'm okay with it. I've become more stoic with age without trying to become stoic. But I couldn't work at a startup company at this point... I couldn't even do that in my 20s I was never cut out for that kind of thing. My mom in her 80s says she doesn't fear death, that she feared death a lot when she was young, but as she got older she just didn't care as much.