There are all kinds of different people in the world, each one of us with a unique set of skills, preferences, and habits. It's our differences that make co-existing with one another interesting: Life would be ridiculously boring if we all thought the same way at the same time.
Sometimes, though, there are things that divide us into groups so black and white that no one can deny it if they tried. For example, you're either the kind of person who has a closet full of white shirts, or you're the kind of person who spills coffee on yourself every time you try to wear anything close to white. There's no point in fighting it, it just is. And while we wouldn't want to reduce human beings to two basic groups, sometimes, it's just too easy.