Clearcase may be the most superterrific software product in the world, but it was horribly complicated to use.
Thanks for saying that; I thought I was alone in the universe.
When ClearCase was brought in-house, all the programmers were given a class in how to use it. With disturbing frequency, the instuctor (a fellow employee) kept telling us to revise the hand-outs we'd been given.
I finally asked why there were so many errors. "It's out-of-date documentation; we were given a good price for it!".