Obama told the story of a student who spoke about her senior engineering project building medical devices for people with disabilities in an African village. When her professor showed a video of the people they had been helping, she said: 'It made us want to be successful for them.' Obama seized on that phrase as a motto for all graduates. He urged them to look beyond their own uncertainty about the future. A troubled child might see a mentor in them. A homebound senior citizen might see a lifeline. The folks at the local homeless shelter might see a friend. None of them care about bank accounts or fame. They just know that you're somebody who cares, somebody who makes a difference in their lives.