This is a question I've long wondered about in Babylon 5. There's a scene in which Bester says to Garibaldi:
"Would it interest you to know that I'm married, Mr. Garibaldi? That I have a five-year-old daughter? That on Sundays when I'm back home, we pack a picnic lunch and go out under the dome on Syria Planum and watch the stars come out? Hardly the description of a monster."
I see two possible interpretations of Bester:
He knows he has questionable methods, but believes he's doing good in the long run, and so, in his own estimation, is on the whole a decent person. Because his methods are questionable, he accepts certain people (the entire Babylon 5 staff) will hate him.
He knows perfectly well he's despicable, enjoys having power and pissing people off, and says these things either to get a reaction, or to look like he's not so terrible.
Has anyone involved in Babylon 5's production, especially JMS or Walter Koenig, said which of these interpretations is true?