Oddly enough, or maybe not so oddly, when I used to be a heavy drug user I would spit all the time, regardless of who was around, and so did all my druggie buddies. I remember having a conversation about it with one of them once. Nowadays, I almost never spit in public, though if it is a dire situation and no one is around then I will if I have to. I probably should have voted for that instead of the "not a chav" option.