Here's how I keep my life interesting and fun:
Pick a career that revolves around things you would do for free. I love to research, write, publish, and make meaningless, superficial relationships appear meaningful and long-term. So I work as a technical writer for major corporations. Ergo, I love my job.
Train for a couple races a year. It gives you structure and demands a good amount of time. This helps me take the rest of my non-working time seriously so I don't fritter it away. Not much anyway.
Downsize your belongings. Once a month or every couple of months go through your clothes, books, dishes, shoes, ties, etc and donate anything you haven't used in a few months. If you forgot you have it then you don't need it. For me this keeps me from getting complacent and getting into a rut. Its a way to make an active analysis of my life and what I am doing. Sadly, our belongings define us and I find myself getting into bad modes of thinking when I engage in the mindless accumulation of stuff. Also, donating stuff is nice; especially if you buy nice stuff.
Get into a hobby/sport that engages your hunting or gathering instincts. Fishing or gardening, for example. This is another way to keep yourself in check since you're engaging yourself at a base level. It's similar to what I think we get from racing, but I think its important to have a second sport that engages your mind and body in a different way.
Dating. Friends.
That's enough to keep you too busy to get angsty.