Short list:
* Pollution and the climate
* Privation
* Avoidable death
* Interplanetary settlement
* Liberty and communication
* Transportation
My primary focus is developing and commercializing reliable clean energy, because I believe that is the most effective way to further progress in the majority of the above problems.
To that extent, I've come to terms with an inability to spread my focus across all of them simultaneously and drive great results so instead I've taken an approach of working on a few of them full time myself and investing in efforts that work on others. My intent is to keep ~100% of my net worth invested in these main problems (either in my own or somebody else's projects) in perpetuity.
In my personal life, I've also recently been spending a lot of time thinking about health and purpose: how to build discipline, how people can/should decide what to do with their life, how to stay healthy and built fitness, etc.
Side project: in my free time over the last few weeks I've also been thinking more about how to create lasting models for information and media, and so I'm building a markup language / static site generator in that pursuit [2]