Fish and chips are the one that most springs to mind - the smell of hot vinegar makes my mouth water and the first few bites are ambrosia but half way in I'm losing interest and by the end I just feel greasy.
Offal is another one. I very much want to embrace nose to tail eating but offal in general and tripe and kidneys in particular just dont work for me. I like to think it's a texture thing rather than squeamishness but I suspect there's some self delusion in that.