Have patience. I'm still working on that one, personally. Most of this other stuff I've seen mentioned, like plumbing, are things you learn as you grow older and experience life... you don't just automatically know them upon adulthood.
Point blank. I don't mean pasta sauce on bread, either. Or cheese on top of some kind of mixed up bowl thing. I mean taking raw food, boxed food, un-mixed food, and creating an edible dish. Especially if a man plans on having a family. Even if he does not, it's still a good thing to know how to do.