Forget about the dumbbells, kettlebells, Olympic weightlifting platforms, pullup bars, cross-trainers and even your lucky deadlifting t-shirt. The most important piece of ‘equipment’ in the entire gym is that guy standing above you on the bench press, making sure you don’t decapitate yourself while going for a new PR.

That’s right: A great workout partner can motivate you, keep you accountable, push you harder and keep you from killing yourself.

But with great power comes great responsibility. Here are the key traits that make for a great workout partner.