To soon: freaks and geeks, my so called life
Not soon enough: Orange is the new black, mad men
I was going to say those exact 2 shows for ended too soon! I loved both of them growing up! I had the biggest crush on Jordan Catalano.
Also ended too soon: Beavis and Butt-head. I loved them making fun of the music videos-that was hilarious! They briefly brought it back a few years ago, but it didn't last long. IMHO, the most recent shows were even funnier than the 90's shows. They made fun of Jersey Shore and 16 and Pregnant.
Shows that dragged on too long:
I have so many, but just off the top of my head-South Park (I thought it was funny when it first came out, but it's lame now), Jersey Shore, American Idol (I thought it was over with, but it's still going on!), Beverly Hills 90210, Dawson's Creek, Felicity, The Bachelor and The Bachelorette, Keeping up with the Kardashians, OITNB and Shameless, but to me, they both really declined in quality as time went on and Shamless lost a couple of their best actors.)
This is probably going to be an unpopular one since so many people seem to love it, but I think Friends dragged on for too long. I just never cared for it that much or thought it was that interesting or funny. Which is strange because I love a lot of movies with Jennifer Aniston in them. Plus it's based in New York City, yet you rarely saw a black person on the show. Come on now! lol