Hell, an HIV viron could be created spontaneously through quantum tunneling in your body with some non-zero probability. I think it would be legitimate to triple equal signs that to "not going to happen" though.
Time spent driving is not time spent having sex (well, hopefully).
So if risk(dying while driving) ~ risk(dying because of sex) ~ 0, you can easily ignore both of those.
Also, you can avoid having sex with a HIV-positive person. You can probably not avoid driving. So the fact that a risk may be low is not sufficient to take such risk if you can hedge against it.
Meanwhile doing some once a day with a 1 in 1,000,000,000 chance of possibility killing you in 40 years just isn’t worth considering.
Depends what your quality lifespan is. If I get sick of everything, that time isn't worth much.
There's also a "time-value" of life.
Cool stuff I can do today may be worth a lot more to me than things I can do 500B years from now. Especially since the person that would be doing them is someone I cannot identify with at all.
Yes, and I believe this is a reason why people make choices that adversely affect their 50 year old self. Who's that guy in the future going to be? Why should I care about making it better for him?
I can imagine time scales on a par with how long I've lived and to a lesser extent to the ages of people I identify with.
(500 year from now me would see the first paragraph as exceptionally foolish... and also inevitable. But that fact doesn't change the truth of what I'm saying).
You don’t need to be a 100% sure. Once the risk becomes small enough you can spend your time worrying about other risks.