I am an old and cynical person, especially when it comes to politicians showing emotion. I always suspect that such displays are rehearsed and aimed to achieving some goal. But I think this clip of Barack Obama getting emotional when thanking his campaign workers the day after the election is genuine.
It sounds like an impromptu speech and is quite moving, especially because he is focusing on them and their future, and not on him and what has just passed. He is humble and you seem him get teary, which is a side of him that was never shown during his campaigns and he has nothing to gain by it after his last campaign for office.