I'm quite lucky. Smoked in moderation for years, gave it up without any problems whatsoever, don't mind being in a smoky pub, though I don't much like the smell on my clothes afterwards - and I very much dislike the smell of tobacco smoke that hasn't passed through someone's lungs to get filtered, for example when people leave their fags to smoulder away in an ash tray rather than stubbing them out.

Pipe smoke is much less unpleasant, and can even smell quite agreeable. I don't know why that is. The same goes for pot.