Knight Rider and The Dukes of Hazzard.
As a child of the 80's, those were *my* shows. I loved them both, and have fond memories of plopping down on the living room floor with my Matchbox cars and watching them. Good stuff.
A year or so ago I discovered that both were in syndication on TNT or something. Set up the DVR to start recording them. So disappointed. I couldn't believe how bad they were. The acting, the stunts, the plots, everything. Just... sad.
On the other hand, I did recently watch a bunch of old Night Court reruns, and found myself moderately entertained. I remember occasionally watching that as a kid/young adult and thinking it was funny, though obviously I didn't get a lot of the jokes. I get the jokes now, and actually think it is/was a pretty good sitcom. So that held up really well. For me, anyway.