From The Fry Chronicles by Stephen Fry:
I was at a dinner party many years ago, sitting alongside Tom Stoppard, who in those days smoked not just between courses but between mouthfuls. An American woman opposite watched in disbelief.
“And you so intelligent!”
“Excuse me?” said Tom.
“Knowing those things are going to kill you,” she said, “and still you do it.”
“How differently I might behave,” Tom said, “if immortality were an option.”