President Obama says being away from family biggest sacrifice of campaign . He also tells the story about his wife and daughter who are in college now. Question about regrets leads to Obama 's lengthy response at French town hall .
President Obama says being away from family biggest sacrifice of campaign . Obama says his lack of privacy is `` frustrating '' Obama says today 's challenges are opportunities for youth to make a difference . Question about regrets leads to Obama 's lengthy response at French town hall .