I've been called every kind of thing, mostly arrogant and pugnacious;
Don't forget prudish and hypocritical!
so it makes a change to be called the opposite.
Actually, no - don't forget that the whole point of Heep's character, the very thing that makes him so creepy and pathetic, is that his "humility", in being so frequently and forcefully expressed, is not only nothing of the kind but becomes the polar opposite. It's like people who make a point of often saying how modest they are - the very act of doing so negates the impression sought. It's called a performative contradiction.