I really only smoke when I have "down time", so I typically smoke at home.
I have smoked it frequently at some social engagements, where smoking (primarily cigs) is going on. Nobody has laughed or made anything but positive or curious comments.
The closest I have come to flat out "public smoking" was in a hotel in Ft. Worth, Texas, when i smoked for a couple days down at the entrance. I talked about tobacco, in general, at length with a fellow who drove one of those rental horse carriages, and I got a couple comments form some well dressed ladies about how the pipe aroma was very nice, etc. Had I been a single man, in this nice Hotel, I would have definitely attempted to parlay those general comments from the ladies into more intimate knowledge of them.
In any case, nobody has laughed at me, or made snide remarks, at least where I could hear them. I would like to think it is because of my intimidating demeanor, but it is more likely a result of a confident one. I think a lot of things about people that I don't remark on publicly. I only expect the same in return.