This thread was made mainly with cartoons in mind, I'm pretty sure, but I agree with Stooge. I've gone back and watched/read quite a few things I loved as a child that just did NOT stand the test of time.
Though I also agree the 90s cartoons were far more intelligent/mature. Hey Arnold alone brought the quality of 90s cartoons above and beyond any other generation's intellectual standards. But I this is due to the thought process of that time in our culture. Generation X was all about doing what shouldn't be done. Be it mixing bright purple with neon green, or putting out a kids show that talked about the tragedy of war and the difficulties of immigration as a Christmas special. Today's generation is less about that, and simply more about having fun. That's why mindless cartoons like Adventure Time thrive the way they do.