There are no stupid questions, just stupid people. Take this example:
Stupid guy: Q - what color is this pen? *holds up a pen w/ a blue cap*
Expected A - Blue, duh
Smart guy: Q - what color is this pen? *holds up same pen*
Expected A - Black ink
granted they should both be able to figure out the answer, but u never know exactly what the person is looking for without a more precise question.