When you disagree with something, don’t ever say “I happen to believe that…[the opposite of whatever it is you're disagreeing with].” Just say “I think” instead. Saying you “happen to” doesn’t add anything (what would it add?) and it sounds pompous. It sounds pompous because it doesn’t add anything. We know you “happen to” believe whatever it is; how else would you believe it, destiny? We all “happen to” believe what we believe; there’s no need to announce it.
It’s just affectation. Avoid affectation. By the same token avoid affectations like “well played, sir” as if you were Samuel Johnson at a game of rounders. (And speaking of Johnson, don’t call him “Doctor” Johnson.) (And speaking of not calling people “Doctor” for no good reason, don’t call Martin Luther King “Doctor” either.) Avoid pseudo-archaic epithets and courtesies, avoid labored jokes, avoid strained metaphors. Unless you’re really good at them, which is unlikely. Don’t try to sound like Christopher Hitchens, or P G Wodehouse, or Lord Chesterfield, or (above all) Julian Fellowes. Don’t try to sound as if you got a gentleman’s C at Harvard in 1922. Just skip all that; leave it right out.