Nevermind vanity. Or the threat of developing an English smile.
I hate flossing. I hate it in theory. I hate it in practice.
Perhaps it's my payback for having zero cavities as a kid and ending up with fairly straight teeth, without having to endure braces ... as an adult, I've broken a tooth while eating lunch, had two root canals, one tooth extracted, four impacted wisdom teeth removed, and now have four crowns. Needless to say, I'm on a first-name basis with my dentist. So I floss, usually in my car on my way to work. (I know, it's weird. But it works for me.)
I do all these things to try and keep the teeth I've got left. And I'm in good company, when I see the health statistics on loss of natural teeth, by state.