I had absolutely no idea that popcorn or fish were problems in office microwaves until I read it on ehell. I love both and had been reheating them for years.
Personally, I gag at the diet pasta meals many of my coworkers reheat -- to me, they're the worst smells possible. But they're what my coworkers like to eat, so I don't complain. They're allowed to choose food they like.
I really think it's ridiculous to police what people heat up or get angry over a specific food. Everything smells bad to someone, because we're all different. If someone gives you trouble over the popcorn, they're the rude one, not you.