Well - it is certainly true generally, but take Sauron in the Second Age. I guess the guy was always full of pride, but still he was clever enough to play his role of Annatar, the Lord of Gifts, to perfection. When Galadriel scorned him to his face, he only smiled humbly... the charmer.
I highly doubt Saruman could have succeeded in a similar situation. He was not of the right character for the role.