Over the past two decades, I've interviewed at least 100 CEOs on topics ranging from strategy, to finance, to management style. The challenge with such interviews is always to get the CEO "off message" and talking human to human.

To do this, I usually ask: "What do you like best about your job?" While the answer isn't generally useful to whatever article I'm writing, it loosens up the conversation, because everyone like talking about what they love about their job.

The most common response is something along the lines of "making a difference" or "changing the world." However, I've gotten some responses that I didn't expect. Here are some of them:

1. Spirited Debates

Some successful CEOs feel frustrated when everyone agrees with them. They prefer working with a team of people executives who have the skills, perspectives and courage to question the CEO's ideas and fight for their own.

2. Beating the Other Guy

CEOs are by nature competitive. However, some CEOs seem motivated less by a need to win than by a need to make the other guy lose. Often this desire is expressed in surprisingly violent terms, like "nuke the competition."

3. The Social Status.

This one answer tends to pop up during the "open bar" portion of industry conferences. I've heard CEOs admit that "I like that people respect the title" and I once had a CEO quote Henry Kissinger's line that "power is the ultimate aphrodisiac." Which frankly was more insight into that CEOs character than I really wanted to have.

4. The Challenge

CEOs must set the company's strategic direction, manage the executive team, be the "public face" of the company, sell ideas to the board of directors, sell the company's future to investors, while also being a role model and inspiration to everyone in the company. It's a challenging job which is why some CEOs love doing it.

5. Mentoring

Finally, some CEOs say that they enjoy cultivating talent and helping people grow. However, such mentoring is entirely separate from the process of grooming another C-level exec to be the next CEO. I have never heard a CEO say that he or she enjoys that part of the job.

What may be the most surprising, however is that no CEO has ever told me that the best thing about the job was the compensation. For the most successful CEOs, money is just a way of keeping score; it's not what motivates them to do the job.