Mostly the whole "IF YOU WANT TO KILL YOURSELF YOU SHOULD JUST GO JUMP IN FRONT OF A BUS" crap. Or, yeah, lecturing me. Or people who throw a fit if they're outside and catch a whiff of cigarette.
Not sure if I've shared this on the forums before, but something I find incredibly funny is when I walk by a group of smokers while carrying an energy drink, I almost always have one of them make the remark that "Those things are terrible for you/they'll kill you!"
*insert Willy Wonka meme here*Please, go on telling me how to be healthy