All of the best entrepreneurs, sales professionals and leaders have at least one. They push us to get beyond our self-created limits. They are change agents in our lives. They are our cheerleaders, pace setters and accountability partners.

When it comes to coaches, I have several, including a business coach, golf coach and a personal trainer. The one quality that they all have in common is that my relationship with each of them is more important than the product they sell.

Related: 4 Reasons You Should Seek Out a Business Coach

Getting people to institute change in their lives is really hard work. The coaches who sustain long-lasting relationships with clients create a dynamic where the client is as vested in the relationship as they are in the results. Here are the four common, crucial qualities of my best coaches:

1. They’re interesting.

I’ve been with the same golf coach, Bill Pappas, for two years. He asked me recently about why I take golf lessons from him every two weeks, even though I never have time to get out on the course due to my schedule.

It was an interesting question that caused me to reflect. I’ve determined that I stick with the golf lessons because I love the stimulating conversation every Saturday morning. He is well read, a phenomenal entrepreneur and we always have interesting conversations about business, life, golf and cool people he’s met and coached.

If he was just a golf coach, I’d have quit long ago because I’m willing to give up on my golf expertise, but not willing to give up on our conversations.

2. They create results.

The most crucial quality to being a better coach is that you must be really good at creating results in your client. For example, I’m not 100 percent committed to being an awesome golfer, but my golf game has improved phenomenally.

Related: Some People Have a Therapist. I Have a Business Coach.

The best coaches don’t hand clients an easy reason to back out or give up. Helping the client achieve their desired results is half the battle to being an extraordinary coach.

3. They do more.

From the first day I started personal-training sessions with my coach, Chi Bang, he’s gone above and beyond his scope of training services. He has shared his professional network, offered business advice and has opened his home to me in times of need. He’s been so good to me, beyond personal training, that I could absolutely never leave him.

This is great news for both of us. There are many days in which I’d like to give up on my personal-training goals, but Chi Bang is one person I will never give up on.

4. They form friendships.

When I go through the roster of coaches I have in my life, all of the ones who have stuck are now my friends. A friend knows how to push you and knows when you are not giving 100 percent. They feel comfortable being frank and they care about you beyond the results they are paid to help you achieve.

I’ve never hired a friend to be my coach, but interestingly the coaches who I have hired and with whom I’ve had the best results are the ones who become more than just a coach. – Stacey Alcorn