What skills are rarely taught but extremely useful?

How to change a tire. As an adult, the amount of people I know who don’t know what to do is astounding. It does require a bit of brute force but the concept of how to do it is as simple as it gets. I even dated a guy once who called a roadside assistant place because he got a flat, didn’t know how to change it and wouldn’t let me do it or talk him through it