Cook's Law of User Experience Design
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
— Rich Cook
User stupidity will expand to fill and find all available bug space. If it's wrong, but a user can get away with it, even if they don't want to do what they're doing, they will break something. Watch what they're doing and try to explain to them, "You wouldn't want to do that" they will say, "I guess so, but it's still the developer's fault." Users don't know what they want. They don't know what they're doing, not even slightly.
In other words, you shouldn't necessarily give the user what they ask for since it is likely to be wrong.