Even when I smoked man, however long ago that was, I don't remember throwing butts on the ground. Not to say I never did but I remember vividly I would put'em out on the bottom of my shoe and throw it in a can. Then again, I haven't been many places without trash cans like here.
Weed, however, totally different. I don't throw toss that, no need, smoke it til the last ash.