Obama did also have some fun with the departing Defense Secretary.“When I took office, Bob Gates had already served under seven presidents, and he carried a clock that counted down the days, hours and minutes until he could return to Washington State with his wife Becky,” Obama said. “I was able to convince him to stay for one more year -- or I was able to convince him to talk to Becky about staying one more year.”He added, “At some point along the way, Bob threw out that clock. He is now one of the longest-serving Defense Secretaries in American history. And as a grateful nation, we can all agree that Bob has more than earned the right to return to private life, which he has decided to do at the end of June.”