Mary O’Rourke said an extraordinary thing about Brian Cowen, whose troubled term as Taoiseach was marked by the implosion of the Celtic Tiger and other colourful combustions.  She said: “He never, ever smiled. In fact, he scowled all the time. He ruined us.” This is a sharper insight than is apparent at first sight. As one whose modus operandi was adding to the gaiety of the nation, she knew what she was talking about: scowling doesn’t inspire confidence.  In this she was an early forerunner of Kamala Harris who unnerved Donald Trump in the big debate with her laugh and…