I JUST DON'T GET IT!
Why is it that most smokers I see just casually throw their cigarette butts anywhere when they're done with their smoke? Do they think its just going to magically disappear? If someone dumped their trash out the window of their home or the window of their car I think most people would call that person a litter-bug and insist that they pick up their trash, yet when someone flicks their cigarette out a car window or drops it on the ground at a bus stop nobody says anything.
The next time you're standing at a bus stop or EL station look around and try to count how many cigarette buts are lying around. I can guarantee your bus or train will arrive before you finish.