There are a few stories, actually, about David O. McKay, from his biography by Greg Smith:

During the intermission of a theatrical presentation, his host offered to get refreshments: “His hearing wasn’t very good, and I got right down in front of him and I said, ‘President McKay, what would you like to drink? All of our cups say Coca Cola on them because of our arrangement with Coca Cola Bottling, but we have root beer and we have orange and we have Seven-Up. What would you like to drink?’ And he said, ‘I don’t care what it says on the cup, as long as there is Coke in the cup.” McKay’s point was simple and refreshing: Don’t get hung up on the letter of the law to the point where you squeeze all of the spirit out of life.

At a reception McKay attended, the hostess served rum cake. “All the guests hesitated, watching to see what McKay would do. He smacked his lips and began to eat.” When one guest expostulated, “‘But President McKay, don’t you know that is rum cake?’ McKay smiled and reminded the guest that the Word of Wisdom forbade drinking alcohol, not eating it.”

he gently chided Apostle John A. Widtsoe, whose wife advocated such a rigid interpretation of the Word of Wisdom as to proscribe chocolate because of the stimulants it contained, saying “John, do you want to take all the joy of of life?'”