What else?

In some countries doctors are trained to ask "what else?" after a patient describes what brough them: the first ailment reported is almost never the one they came for.

People are similarly very bad at asking for help in the workplace: they rarely come up with the the real problem and you have to dig to find it. When someone reports a problem, ask "what else?" until you're certain you've gotten to the bottom of it. Even if that person is yourself.