I think the best way to pick what you want to do is to find
  the intersection of what you’re good at, what you enjoy,
  what the world needs, and what the world values.

Notice how "what you need" is not listed. The classic startup founding advice of "solving a problem you have" has led to oversaturated markets solving 1st world problems (e.g. food delivery.)

Don't be afraid to look for people who need help and about whom you know nothing. Empathy will take you the rest of the way. When we started Seneca Systems, we knew nothing about local government, but no person is too far away for you to ask questions and understand what they need.