Couldn't Give a Rat's ...

According to John Howard's memoir Lazarus Rising, Peter Costello is a lousy backstabber. That's lousy as in "lousy lover":

Mr Howard says Mr Costello ruined his chances of taking the top job by trying to push him into retirement through media pressure, a move which he says "completely misread both my temperament and my personality".

If Peter Costello did misread Howard's temperament and personality, he's not alone on that score. I can think of one former Prime Minister who consistently made the same mistake.