Robert Jordan's Wheel of Time
Most my friends like this series. I'll admit, I read the first few. Then all the characters became crappy, and I realized it was set up kind of like the war in Iraq--with no exit strategy. The first book in the series was released...wait for it...over seventeen years ago. I realize great literature takes time...but it also tends to be well written. Wheel of Time isn't. I went back to try to re-read the series at one point, and I just couldn't stomach it. There's better literature out there that demands my attention. There's just nothing in these books that deserves my time.
I enjoyed these as a teenager, but I can't stand them anymore. Any of them. Guess I like a little meat with my escapism. I don't care much about the characters, the plots are usually tired and sound rehashed, and the writing style sucks.
See my comments about Terry Brooks
Stephen King: Dark Tower series
Most other fantasy that people actually know about fits into this category (see my other list for the rare exceptions). Some of it (McCaffrey, etc.) I read just a little bit before putting it down, realizing that it's not all that great. It can be fun, but there's no real thought to it, and I come away thinking, "I just wasted how many hours on this?"