I can't say I was ever really picky as a child, but I always hated "orange vegetables" like winter squash, sweet potatoes, and carrots. As an adult I realized it wasn't the vegetables themselves I hated, but the fact that my mother always served them drowning in marshmallows or brown sugar. I've since learned to love orange vegetables, but only as savory dishes.
Same with fish and pork. Mom, bless her heart, cooked both to the point of inedibility. I love fish now and, if properly cooked (or in raw applications like sushi), I prefer it over almost any other meat.
I loved my mother dearly, but even she would admit she wasn't the best cook.