What's your favorite question for discovering product ideas?

I like asking people "What is the one thing you encounter in your job that should be better?" Things I find useful about this question: * "the one thing" - constrain the answer to a single idea * "you encounter" - an act or practice that the person actually does themselves * "in your job" - I like to focus on business related product ideas * "should be better" - fairly open ended and allows for creativity and an outlet of frustration. Everyone knows something about their job that should be better, but many have simply accepted the fact that it won't be. What's your favorite question for uncovering product ideas?