I carry a lighter. I don't smoke, so people often ask me why I do. And It only comes in handy about once or twice a month, if that often. I don't need to carry one. If someone had once drilled into my head that I'd need a lighter and I refused to carry one out of spite, I could probably make a similar boast to them.
But I'd miss out on one or two chances a month, maybe less, to be useful.
I also usually carry a knife, but haven't had one for about a month now. I notice every few days situations that are a lot more difficult than they would have been, if I'd had a knife. I get around them. Sometimes I just don't speak up. In never would have noticed how much easier these things could have been, if I had just had a knife, if I weren't used to having one.
That's sort of how I feel about not knowing math. Opportunities to solve problems easily, gracefully and quickly must pass me by every day because I didn't manage to internalize the algebra and geometry I should have learned in high school.
I don't see them, just like I wouldn't have seen opportunities to use a knife, or a lighter, or paperclips or tape or any other of the assortment of things I've had on me at opportune times.
Sometimes I feel like the biggest difference between successful, lucky and talented people, and downtrodden, unlucky people, is keeping up habits of being prepared for the right kinds of problems you'd never have noticed if you didn't know how to fix them.