The gist: You’ll mirror the habits of the people you spend the most time with. To build good habits, spend more time with people who already practice them.

The other day, I was watching an episode of Shark Tank—a reality TV show where struggling entrepreneurs offer up a piece of equity in their businesses for a chance to work with successful business people.

In this episode, one of the entrepreneurs ended up giving away a bigger portion of his business than he originally intended to close a deal with a shark (investor).

It was the right decision to make because his business was going to fail without some outside investment and guidance, but it was what he said during his exit interview that really struck me:

“Hang around four broke people and you’ll be the fifth. I’m glad I got a deal with one of the sharks.”

What he’s talking about is the proximity effect, and you can use it to improve important pieces of your own life.