A few weeks ago, I attended the Banff Mountain Film Festival here at our National Geographic. The evening consisted of eight films of varying length, with subjects like Nepal long-distance runner Mira Rai, kayakers in Iceland and skiers in Siberia. But after about the fifth one, my interest level started on a downward slope. At the end, I was exhausted. If they would have stopped at five, I would have left exhilarated.