It depends on the day. I could list 3 here, but then would immediately feel bad that I didn't include other issues as they spring to mind. But the first three that pop into my head:
1) Gun Control. The issue I know I'll never "win" on, but boy... it would be nice if I didn't have to worry every time I went to the mall/movies/sporting event/anywhere in public that some psychopath might just start shooting everyone up. I'm not saying "ban all guns!", but... common sense, man. More restrictions on types/amounts you can own, etc.
2) Basic equality issues. What used to be "gay marriage", and is now basically bathroom issues. Every adult American should have the same basic freedoms and rights as each other. Marriage, adoption, sex life, ability to not get killed by the police, etc.
3) Balancing spending. Not a debt or a budget issue, but just changing what we spend our taxes on. More money to infrastructure, first of all. Let's quit having dangerous overpasses and collapsing roads. More money to healthcare and education. Less to the military and all the agencies just spy on us. Let's quit arming cops like they're about to go fight an intergalactic war, while we're at it.