Where do you get your ideas?

That question, more than any other, seems to be a bugbear for writers and other artists.

I find it embarrassing, myself. Not because it's hard to answer, and not because the answer (from my brain) is so obvious and anticlimactic. It's because I inevitably hear a question behind the question: why is it that you have good ideas and I don't?

It can't be true that the asker has no ideas, or really doesn't know where ideas come from, right? Those aren't possibilities I can entertain, and I am the...