Thread: "Stupid questions"

What are your opinions on "stupid questions"?
My impression is that most people consider questions with an "obvious answer" to be stupid questions, and that they could easily find the answer within a couple minutes - and sure, it might seem a bit funny if someone asks a question that has a very obvious answer.
However, the problem I see with all this is that this creates an uncertainly on what questions are "smart enough" - for example, if you are present during a lecture and you are uncertain about something, then how can you be sure that your question won't turn out to have an "obvious answer", and make you look stupid to everyone else?
This sort of uncertainty often makes people hesitate to ask questions at all, which I find highly detrimental in all sorts of ways.
Personally, I think that whenever someone asks a serious, polite question, then that person should at least be treated with the same respect and get a clear answer - and I think it is much better to ask questions and get answers, since this is how you learn new things.
But this is just my personal opinion.

What are your thoughts on this?