Great salespersons love their craft. Albert Reynolds didn’t dispute the story that he once sampled pet food from his Longford factory to help convince buyers from Sainsbury’s that they should award him a contract. Ben Dunne was another driven by a passion for selling. So were the Quinns – Fergal, and Pat.  One cold December morning at Belfast’s Aldergrove Airport, I saw Michael O’Leary in action. He had left Mullingar in the darkness to drive north. Then and certainly now he was a multi-millionaire. But he had no reservations about donning a Santa Claus costume and handing out promotional flyers about…