Now, smoking is a personal decision. Me, I don't like cigarette smoke, but if you do, that's fine. There's no reason we can't all get along if we're just polite about allowing smokers to be near smoke and non-smokers to not be near it.
Littering is another matter entirely.
People using the ground as an ashtray makes me cranky.
So after getting out of my car, I went over and picked up the (still-smoldering) cigarette butt and walked over to the offending car. The driver was still in the car, so I knocked on the window to get her attention. She cracked her door a little, and I said, (in a polite tone of voice), "Excuse me, I think you dropped this."
And she said, "Oh!" and took it. Kind of as if it was, in fact, some kind of accidental mistake. So I kind of half-smiled, as if we had completed some normal random-stranger interaction. And then I left.
I'm not really sure what the point of this story is, unless it's to share what seems to be (in my experience) an effective and mostly polite way of providing negative feedback to someone who is exhibiting socially unacceptable behavior.
I think it works, so I'm glad I did it. (Though it is a little bit obnoxious, and I feel sort of sorry about that.) But mostly I just wish it was unnecessary.
I think it was karmic payback that my fingers then smelled really awful until I got to Jeff's and washed them.