This commencement address by Dropbox founder and CEO Drew Houston is terrific. He’s speaking at his alma mater, M.I.T., and he’s only been out of college since 2005. He tells the story of how he got started as an entrepreneur, and he offers some great wisdom about choosing work that challenges and delights you like a “dog chasing a tennis ball”:

When I think about it, the happiest and most successful people I know don’t just love what they do, they’re obsessed with solving an important problem, something that matters to them. They remind me of a dog chasing a tennis ball: their eyes go a little crazy, the leash snaps and they go bounding off, plowing through whatever gets in the way. I have some other friends who also work hard and get paid well in their jobs, but they complain as if they were shackled to a desk.

My dog, Mosley, certainly gets crazy eyes when I fling a ball across the yard. He could be waking from a nap, but if he sees me with a ball in hand, he comes to life in a flash. I feel that puppy-like excitement when I get caught up in creating something worthwhile or working on solving a problem and making a dent in the universe.

I love how Houston concludes, with the call to tell an interesting story with your life:

Every day we’re writing a few more words of a story. And when you die, it’s not like “here lies Drew, he came in 174th place.” So from then on, I stopped trying to make my life perfect, and instead tried to make it interesting. I wanted my story to be an adventure — and that’s made all the difference.

We’ve got a limited stay here on this planet. If we’re lucky, Houston points out, we might get as many as 30,000 days. Today is my 49th birthday. I’ve lived 17,885 days, and I’m delighted to have made it this far. But I’m on the back side of my days. I just want to make the ones that are left worth talking about.