David Steindl-Rast is a monk, and a composed, serene figure to wrap up the last session of TEDGlobal 2013. His theme, gratefulness, is also appropriate for the end of a long and intense week. After all, he points out, we all share the same essential goal: to be happy. And gratitude provides the key. "We all know people who have lots of misfortunes that we ourselves would not want to have, and they are deeply happy, they radiate happiness," he says.