To make my transactions being processed fast in cause of %whatever_happened%, for example. And because it's my money and I want to control it by myself, not by algorythm. And at last because I can. So, I'll stick with 0.5.11, I guess. It's your program of course, and you choose how to develop it, but why make slider, why not just field pre-filled with automatically calculated fee which I can change? Why you disable me to change fees? I'm not a new user, I can worry about fees by myself.