When Wal-mart President and CEO Mike Duke recently made a surprise visit to a store in South America, he was in for a surprise. While he was delighted to see that the store was doing well, he was taken aback when the store manager told him, “I am glad you made a surprise visit. I would have never slept last night had I known that you were coming,” Duke recounted the episode last week when addressing employees at the Wal-Mart International Associate Conference at Fayetville, Arkansas.