I try to keep my serious levels in deveolpment to perfect them as much as possible before betatesting. Add this with the fact I sometimes lose intrest in certain projects for while, and there's a recipie for levels never being released.
The fact I don't like you means you personally have never seen any of my WIPs which I occasionally send around.

The most serious levels that I ever released were for the little-known ABSP pack, these levels were horrendusly rushed, but at least the Heaven level isn't complete crap.