Social media is supposed to allow communication and bring people together, I can't mention a social media site that actually does this, theres a need.
Our broken monetary system that makes the rich richer and the poor poorer. But then again theres enough crypto currencies in the world.
Representative democracies are broken there needs to be a distributed cryptographically secure voting system.
Things that don't
Volunteer at local charities, they have lots of stuff they should automate but don't have the skills to do so. Most will get you doing the general volunteer work that can be done by anyone, this is a mistake as they won't understand what you can do you need to make them aware how they should be using you and your skills.
Take your problem solving skills to a new job / career and solve problems with something other than software.