Brussel Sprouts. Absolutely hated them as a kid, which I blame my mother for. She "steamed" them in the microwave in a dish with water. Turned them into a slimy, horrible mush. My wife sautes them in a pan, with bacon. It's one of my absolute favorite dishes now.

As a kid, I thought I hated steak, but it turns out, my mom was just really bad at cooking steak.

Black coffee. Used to only drink coffee with creamer or lattes/cappuccinos, but now I drink black because I can't stand the sugar crash

Sour cream. As a kid, I didn't like it. Now it's essential on my tacos, pierogi, and chili.

Tomatoes or mushrooms. Both were a texture thing. I made some diet changes as an adult, so I’m not sure if that helped in changing my opinion, but now I’m fine with mushrooms and grow tomatoes in my garden every year!

Eggplant. I tried cooking it until just tender, like zucchini - and it was nasty as hell; I never got it and never wanted to.

Then I encountered some actually properly cooked stuff in a pasta dish when eating out and ohmygod.

tomatoes. hated them as a kid. juicy burgers were may gateway into them.

Same with vegetables, but also steak and bacon. I hated steak and bacon as a kid idk what was wrong with me

Sweet potatoes. Something about them made me gag. Every Thanksgiving a heaping pile of them would wind up on my plate and I'd have to power though or else face the wrath of my grandmother.

Nowadays I love them. Dunno when the switch happened.

Both chili and vegetable soup.

Never cared for either growing up, but now they're both comfort food, especially on cold days.

Olives. I still am not a fan of black olives, but I'd eat an entire jar of green.

I heard that stuff like green vegetables are unpalatable to children because they taste more bitter to them.
As you grow up you become more insensitive to those flavors and start tasting the other compounds that you actually like.

Fish in general. As a kid I absolutely disliked the strong taste and oily texture.

I'm very open with my foods and like to retry everything I disliked in the past, things I still don't like are Olives (weird metallic taste I don't like), Tomatoes (slimy texture at normal size, cherry tomats are fine), unaltered boiled egg yolks (so dry, so so dry), Oatmeal (texture issue), and a couple others I can't think of at the moment. I enjoy most of the texture based ones as soon as the texture is altered.

Sauerkraut was just too overwhelming as a kid, but I love it now. Some other foods were the same, but that is the one I remember.

I liked black olives as a kid, then hated them in my teen years through early 30s and find them tolerable now.

A lot of people hated vegetables as a kid if they were made bland by boiling, and like them a lot more when they have them roasted or just with some seasoning. I remember having bland steamed brussel sprouts at home which are just awful but one of my friends roasted them and they were awesome. My dad cooked up some awesome seasoned steaks and that friends parent bought the wrong cut and cooked it well done so it opened my eyes to how much of a difference preparation makes.

Anchovies on pizza. Just a couple though, like fish sauce, a little goes a long way.

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.

Onions

Gumbo. My mom made it a few times and I always hated it. Turns out she wasn’t making it correctly until I had my extended family make it the way our family did from Louisiana and now I can’t get enough of the stuff.

My family goes all out on gumbo, making a pot that will cost around $400 (pre-pandemic pricing, not sure how much it went up since) but have every little thing everyone wants from shrimp and sausage to chicken and all the little fixings in it.

i used to hate peanut butter. idk why

Brussel Sprouts with black pepper 🤤👌

Pig and chicken feet. Fat is so good.

I fucking love Cauliflower, I thought I didn't like it because I grew up poor and didn't really get fancy veggies

Pickles. They were too strong and sour for me. Now I love 'em.

Swiss cheese

Wine

Have always had a pretty broad palate but swiss cheese I couldn't like until I was older, and could taste its flavor relationship to good Parmesan, the nuttiness.

Wine I made a conscious effort this year, that wasn't a maturity thing, it was a project but have found several I actively enjoy rather than just barely tolerate.

Oh, and turnips - I didn't like them, then I enjoyed them raw with dips, now I do like them raw or cooked.