Dumb questions about software

Sometimes I think how can be possible that so many people can question barbarities, without realize of the dumb they seem to the eyes of the computer specialist. However, they would think that themselves are dumb if they made equivalent questions to other professional, for instance, asking an automotive engineer: how can I turn on the radio of my car?, or an architect: where are the plugs of my house?. But, ask a computer specialist: how can I change the screen background of my mobile? or how can I print in color with my printer?, this seem to them that is the most normal of the world.

When someone makes me some question of this kind, although they get angry, I answer that is better that they learn to discover it by themselves. In this way, the next time they don't forget it. If your answer is that you don't know it, also they will say: how? don't you know it? Aren't you a computer specialist? Then you have to explain that a computer specialist isn't the person that know how to use all the software of the world, but the one that knows develop software, but they don't listen, and sometime after, they do a similar question. This kind of people usually doesn't have a lot of technological knowledge and, normally, they don't ask because they want learn, but because they want that you solve the problem and forget it. For that is better don't lost the time giving an answer. What do you think?