When you're the CEO of a company, you have a bunch of people reporting to you. The board, as others have pointed out, while supposedly an authority, tends to be a social club in many aspects. In the end, you generally find that most of the people who surround a CEO tend to kiss his or her ass.
It's no different than a smaller version of becoming a celebrity. (When hundreds of thousands of fans spend time fawning over you, it's hard not to lose your head.)
It makes those people who can resist such things all the more special.