I'm 46 and rode the Web revolution to a great career, working for some amazing places, and I'm still worried about some of these things. I've done a lot of things I'm really proud of, and I still don't feel done, so trust me, this never goes away and maybe it doesn't even make you lost, just searching.

One approach I can suggest: in my generation if you wanted to change the world you went into nonprofits, which is what I did. You don't have to build a startup on one of your own ideas to make a difference. What are your causes? What do you care about?