The thing that springs to mind for me is cooked fish with the heads still on and the eyes staring blankly...
Brrr! It must've just got very cold in here coz I'm shivering.
Russell
The eating/spitting/picking things are all gross of course, and I'm with Lost on the lost consonants etc - but what really makes me shudder and goose-pimpley even as I type is someone biting into an ice lolly.
(Some things should really only be sucked and licked.)
From my school days, the scraping of chalk on the blackboard.............
Don't want to sound snobbish (I'm not at all) but hearing people say "sumfink" - it isn't an accent, it's sloppy.
Stepping on a snail in my bare feet and getting that CRUNCHSQUISH feeling/noise. It goes right through me. Specially when I have to pick the remains out from between my toes. UUURRGGHH