I presume it was microwave popcorn in a bag? I don't like the smell of that stuff, either. Classic popcorn is OK to me, but those bags contain a special oil mixture that heats quickly from the microwaves, as compared to regular vegetable cooking oil you use in an old-fashioned popper, with peanut or coconut oil being common. There are also hot air poppers that use no oil, and have the least smell of all.
And some of those bag oils contain optional "buttery" flavoring, that reeks even more to me. There's also been some controversy over health issues with those oils, so I just avoid the stuff.
If we're talking only about food, certain heavy, greasy frying smells actually turn my stomach. As can almost any smell if it happened to coincide with my having a nauseating sickness, like the flu. I'll then have flashbacks of nausea around that food in the future, an effect that's sometimes persisted for years afterwards. Fortunately it's been so long since I last had the flu that I've got no foods like that at present.