A lot of shows that I watched as a kid rarely seem all that great upon watching years later as an adult.
Speed Racer,
Robotech
others..
But I guess that's to be expected, as people's tastes change, and some of these are now so bad they're good.
Thinking a little more to more modern series, I tried to go back and watch the rest of Seiken no Blacksmith (Sacred Blacksmith) but gave it up as it didn't seem as interesting as I had remembered, at least not enough to get back into it. Maybe someday...