It can be tough to win the GUI war.
If you program all the function buttons for something like a cable or sat box on a touch screen, you end up with a lot of buttons and some clients that look at it and become afraid to use it. They often have no idea what 1/2 the buttons do (never used the PVR/DVR functions and don't even know what it means)
All they want is guide, the arrows, CH+/- and a number pad.
Or you get the other type who wants total control over absolutely everything, like treble bass etc.
I have had a client ask me what the right arrow button (play) did.
It did not say play, so it was not obvious to him.