I never really liked iceberg lettuce in the first place, but the weekend before I started high school, my grandad was visiting, and he boiled an iceberg lettuce having mistaken it for cabbage. The end result could only be described as a green mess, which I couldn't bring myself to eat. It put me off ever trying it again.

As for the non alcoholic beer and indigestion, I remember when I was about 7 and Dad had tried some non alcoholic beer at...I want to say his work Christmas party, and the memory of his reaction at the time put me off that too.