I absolutely DESPISE watching, seeing, smelling, or hearing people eat. I think it's disgusting. Now, don't get me wrong, I think you can actually learn a lot from someone by the way they eat, and because of this I force myself to do it when I'm looking for some character inspiration for a story. However, it's not something that I, by any means, enjoy doing.
I really don't want to see what you're eating once it's gone into your mouth. Really, I don't… it's not necessary.
My other one, which is actually food related as well, is sharing straws with someone. I can't do it. Even with family. People don't make sure that their mouth and/or lips are clear of food, and there is almost always some kind of food particle or other left either on or in the straw.
Gahh… I'm totally grossed out right now!