The two men at dinner were clearly on the same wavelength. One of them was my friend Jon Katzenbach, the former McKinsey & Co. director who now heads his own elite consulting boutique. The other was Niko Canner, his brilliant partner. They were planning a new venture. But something about their conversation was slightly off. When Niko floated ideas, Jon tended to interrupt him. "That's a great idea," Jon would say, "but it might work better if you . . ." and then he would share a different way to tackle the issue. When he finished, Niko would pick up where he left off, only to be interrupted by Jon again. Back and forth it went, like a long rally at Wimbledon.

As the third party at the table, I watched and listened. I do this for a living as an executive coach. I help smart, successful people identify interpersonal challenges that they can improve -- and then coach them to get better. I'm used to monitoring people's dialogues, listening for clues that reveal why even the most accomplished people may sometimes annoy their bosses, peers, and subordinates.

Ordinarily, I keep quiet, but Jon was exhibiting classic smart-person behavior. When Niko left the table, I laughed and said, "Jon, perhaps you should just go with Niko's ideas. Stop trying to add so much value to the discussion."

In my experience, one of the most common challenges that successful people face is a constant need to win. When the issue is important, they want to win. When the issue is trivial, they want to win. Even when the issue isn't worth the effort or is clearly to their disadvantage, they still want to win.

Research shows that the more we achieve, the more we tend to want to "be right." At work meetings, we want our position to prevail. In arguments, we pull out all the stops to come out on top. Even at supermarket checkouts, we scout other lines to see if there's one that's moving faster.

In Jon's case, he was displaying a variation on the need to win: adding too much value. It's particularly common among smart people. They may retain remnants of a top-down management style even if they don't want to. These leaders are smart enough to realize that most of their subordinates know more in specific areas than they ever will, but old habits die hard. It's difficult for them to listen to others disclose information without communicating either that they already knew about it or that they know a better way.

The problem is, while they may have improved the idea by 5%, they've reduced the employee's commitment to executing it by 30%, because they've taken away that person's ownership of the idea. Therein lies the fallacy of added value: Whatever is gained in the form of a better idea may be lost six times over in the employee's diminished enthusiasm for the concept. One of my top clients said, "Unfortunately, at the CEO level, my suggestions get taken as orders, even if I don't want them to."

Later on, Jon and I had a laugh over the dinner incident. As one of the world's leading authorities on building teams and instilling pride, he knew the right answer. He was amazed at how often he had said "but." That's how pernicious the need to win can be. Don't get me wrong. I'm not saying that bosses have to zip their lips to keep their staff's spirits from sagging. But the higher up you go in an organization, the more you need to let other people be winners and not make it about winning yourself.