Oh there are so, so many awful movies that I loved as a kid that I have a positive memory of but would be better off not watching again to ruin that memory.
Legend would have to be one of them. It’s still a spectacle to watch, and Tim Curry is incredible as Darkness, Robert Picardo is Meg Mucklebones, but it’s so far over the top it’s a fever dream.
Cave Man with Ringo Star, Shelly Long, and Dennis Quaid. Laughed so hard I cried when I was a kid. Watched it again not too long ago and it’s pretty bad.
Whoopee Boys, same as Cave Man. Cannot rewatch.
Buckaroo Banzai, Revenge of the Nerds, so many other bad movies I loved as a kid. Most of the cheap action films too. Schwarzenegger’s, Stallone’s, Van Damme’s…so bad, lol. There were some absolutely great ones, though…the original Predator (‘87) comes to mind.