Jeffrey Sonnenfeld quotes:

What distinguishes exemplary boards is that they are robust, effective social systems . . .The highest performing companies have extremely contentious boards that regard dissent as an obligation and that treat no subject as undiscussable.

As a leader, you have to not only do the right thing, but be perceived to be doing the right thing. A consequence of seeking a leadership position is being put under intense public scrutiny, being held to high standards, and enhancing a reputation that is constantly under threat.