Nothing motivates me more than a reliable work out partner. If I don't feel like going, he threatens to kick my ass, calls me a pussy, etc... If he doesn't feel like going, I return the favor. I rarely miss time in the gym because of this. Plus, in addition to the gym, you get some, "Time with the boys," to talk about broads, booze, cars, motorcycles, and whatever else you're into (is there anything else?).