You be hopeless. 
As a kid, I loved long cross-Pacific plane flights, to the point where I even suggested that some airline ought to operate a long-endurance airplane that specialized in flying around the world (or, even, just circling about aimlessly in the sky) for 24 hours and landing passengers in the same airport they started. It took some kind-hearted grown-ups to explain to me that there wouldn’t be any, uh, demand for such a service.
Now, I still like flights, but only if they’re very short, like less-than-3-hours. The Pacific flights are abhorrent to me.
I also liked watching boxing when little, now I hate the idea of seeing people give each other violent CTE on television.
My story is not too far from this. Mine involves that white frosting on store-bought cakes. When I was 7 or 8, I ate a bunch of cake one day and vomited twice that night. I can’t stand that crap anymore.
When I was young, I had a great fondness for tomato juice. It was my go-to beverage whenever we stopped at a cafe or snack bar. Then one day, my mother made a tomato aspic as part of dinner. And that might have even been ok, but she had to include in it the one thing that is intolerable to me: green bell pepper. A taste of that put me off tomato juice for the rest of my life.
VC Andrews novels. Yikes.
Another vote for Cap’n Crunch. Loved it back in the 60s, though I still remember how those sharp corners sliced up the roof of my mouth. Tried some recently, and it’s been domesticated: less sweet, less “off” tasting, and it din’t hurt my mouth. But I was just “meh…” about it.
Unlike Lucky Charms. Those fakey marshmallows and oat shapes have held up. It’s my treat when my wife goes on a trip.
And my college housemate’s girlfriend (now wife) was one of the Campbell’s Soup Twins.
Excellent example! I should have thought of this.*
(I also recall, at about age 20, realizing that most adults actually prefer the aisle seat. That would make no sense to me as a child. Who would willingly give up the excitement of looking out a plane window?)
*Though it does violate the OP’s request to not include things that most of us outgrow, vs. realizing they always sucked, inherently. But I think that’s usually an impossible distinction. If a cartoon appeals to children, or a hair-metal band to teens, can we really say it inherently sucks? Philosophers of the arts (aesthetics) have debated this for millennia.
I’m right there with you @burpo_the_wonder_mutt. The factory tour was just the warmup to the main rides at Hershey Park, and the chocolate smell was the warmup to the factory tour.
For me, I thought fast food burgers, especially McDonald’s, were like Ambrosia. The best dining experience that my little brain could imagine. My tastes have changed noticeably since then.
Another Chef BRD hater here.
I also tried to rewatch The Incredible Hulk as an adult. I couldn’t do it because it was too slow and boring.
Frankly, I’m surprised I even liked it as a kid. Not very many Hulky parts.
Chewing Gum. What a repugnant, disgusting and filthy habit.
When my kid was 10 (two years ago) l, we watched a “Six Million Dollar Man” episode together, and it was pretty bad.
More recently, I had him watch a single episode each of three classic sitcoms (the first two well regarded by critics as well as viewers): “I Love Lucy,” “All in the Family,” and “Happy Days.” All three weren’t bad, for him or for me. I’d say “All in the Family” held up the best — and made for interesting conversations about which social norms have gone beyond even the then-progressive ones in the show, and which have gotten stuck in a rut (or worse).
Two media examples for me.
The Chronicles of Prydain, a series with weird popularity where the second book, The Black Cauldron, is best known, obviously because that was the one that won awards and the movie was named after. I reread the first one with the idea of introducing it to my kid, and I was so completely bored by the simplistic story and style that I didn’t bother.
And my unpopular choice, A Wrinkle in Time. It was the same thing. I was again astounded by how boring and contrived the story was (Prydain is also very contrived).
Many books I loved as a kid have held up for me, Tolkien and Le Guin in particular, so it isn’t just a problem of making allowances for their intended audience’s age; I just couldn’t like them again.
I recently bought a can of their ravioli, after decades. I used to love that stuff. Pity.
I was on the traling edge of childhood when the pilot aired, as a “two hour” TV movie. It was not great, but it had qualities that made it ok. I could see that they were going to make a series out of it, and that all the things that made the movie watchable would be eliminated in favor of vapid action stuff. I was not disappointed: the series was every bit as pathetic as expected.
So, really, show your kid the movie if you can. It is far better than any episode of the series.
Will do - thanks!
Fish sticks.
Plane travel. It was a rare and strangely wonderful experience then. Now, I’d prefer dental work.
Also, I could be excited to go shopping in a big store back then. Um …
I loved Nik-L-Nip wax bottles when I was a kid. I knew the syrup had a bad aftertaste, but the concept of the things drew me in. Also, there was a version of them that showed up at the Ben Franklin store every Halloween season. Instead of the bottles, they were wax figures including skeletons, witches, pumpkins, etc. They were sold separately for a penny each. Alas, one year those didn’t show up and were never seen again.
Fast forward from the late '60s to the day after Christmas, circa 2018. I find at Albanese in Hammond a selection of the wax cylinder kind. Of course I get some. They tasted even worse than I remembered! My niece-in-law liked them, however.
It seems the preservatives used in the syrup taste bad to some people including me while being tasteless to others. It’s the same in many things, including those freezer pops in the plastic tubes and the biscuits that come in the exploding cardboard tubes.
Campbell’s Chicken Noodle Soup. It was the gold standard of soup when I was a kid. As an adult, I realize most canned soups are not great, just because of the compromises necessary to preserve a mostly liquid food for long periods of time. But Campbell’s red and white branded can soups, for the most part, are especially bad; just awful, insipid salty dishwater.
The one exception is their “Bean with Bacon” soup. Whatever morsels of bacon it may contain are mostly microscopic, but it is chock full of beans, and pretty darn tasty. I still pick up a couple cans now and then to keep for a quick cheap meal, or for the apocalypse.
Worked every time. IIRC, the park was free admission, you bought tix for just the rides you wanted and the factory tour was free or very low priced, so Dad was happy not shelling out a buncha bux before the day even began. Which meant he might have a few extra dollars in his pocket at the end of the day and instead of heading home exhausted when the sun goes down, he might spring for a Mom & Pop Motel room and it would not be tough at all to convince him to hit Strasburg Rail Road, just down the lane, the next day. Which was what he wanted to do all along, so he’s happy. A few fun hours exploring trains then head for home with maybe a quick stop at Henry’s Hamburgers so Mom doesn’t have to cook, so she’s happy. Home by 4PM with time to unwind before bed. The Good Olde Days.