For me it was eggs. My mom wasn't that great a cook and she'd only make two types of eggs: hard boiled eggs or these sort of way way overcooked sunny side up eggs. Never liked either so grew up thinking I just don't like eating eggs.
Later on as I got older I realized there are other egg dishes and I actually really like eggs. Scrambled eggs is pretty much my favorite breakfast. A close second is egg and cheese on a bagel.
Eject the core!