Cigar smoking in public. I'll admit to hating smoking in general, but I think its rude as eff to light up a nasty ass smelling cigar with a bunch of people around. If you want to chill and smoke a stogie fine, do it at home or away from other people.
There is an old man who goes for walks on my street when the weather is nice. He is always smoking a cigar with one hand and carrying a container of water in the other hand. From a distance, the cigar smoke is pleasant but I agree that smoke in confined spaces is gross.
Also, when I was a kid, there was a man who would stand along the sidelines at our high school football games smoking a pipe. It smelled really nice in the cool fall air.