Ask HN: What problems do some of the successful startups solve?

Most successful startups or products solve a problem. It would seem intuitive that most people/users can explain the problem in one simple sentence, but many people can't or have different opinions.

How would you describe it for products like Uber, Spotify, Airbnb, Netflix, Bird or whatever you find interesting?

Examples Tinder: It's awkward to approach and start a conversation with someone in public.

Expedia flights: It's too hard to find the cheapest ticket possible airline by airline.