Mussels as they make me vom about an hour and a half after eating them. I like eating them, though, just not the projectile inevitability.
Overly processed stuff - mushy peas, McDs and other fast food outlets. (This does not include Oxford's fleet of kebab vans - but only after BEER)
Fried full belly clams - like eating a deep fried working dock.
That's it, though. Some of the food mentioned on this thread is on my favourites list, especially capers, anchovies, mackerel (smoked or unsmoked), kidney, liver, goat's cheese, blue cheese and pickled herrings. Mmmm, herring.