I haven't read the other responses yet, but oh boy is popcorn a volatile work topic!
I am not easily grossed out or nauseated at all. As in I had no problems eating when I worked emergency shift at an animal hospital, or at a human urgent care, or while reading my husband's forensic sciences magazines.
Microwave popcorn, however, I find nearly intolerable. The plain stuff I can more or less handle, but the stuff with the fake butter makes me feel sick to my stomach and sends me into coughing spasms (no, I don't have asthma). When someone at works makes that stuff, I avoid the break room until the smell dissipates even if I'm starving.
Burned popcorn smells awful, but for me it's not as bad as the unburned fake butter stuff.