You ever see a dog that’s got its leash tangled the long way round a table leg, and it just cannot grasp what the problem is or how to fix it? It can see all the components laid out in front of it, but it’s never going to make the connection.
Obviously some dog breeds are smarter than others, ditto individual dogs - but you get the concept.
Is there an equivalent for humans? What ridiculously simple concept would have aliens facetentacling as they see us stumble around and utterly fail to reason about it?
I think uncertainty plays a big role here.
You could bump a line and smoke a pack a day and get to 90.
You could do nothing harmful and die at 30.
Even if you make it to 90 avoiding lots of fun, was it worth it or would you rather trade 20 years for more fun?
At the end of the day it is a matter of personal risk tolerance towards an impossible to quantify risk.
As someone who treated their 20s like that, I strongly suggest at least dabbling in restraint along the way. Hell, shibari counts.