It is a very disconcerting thing to wake up at 8 a.m., and an hour later to be watching a documentary about cannibalism, but that is how yesterday began for me.

The documentary Stranded recounts the famous story of the Uruguayan rugby team whose plane crashed in the mountains of Chile in 1972, forcing some survivors to resort to drastic measures to stay alive. It is a reasonably good documentary, and obviously the story -- told here, for the first time, by the survivors themselves -- is compelling. But at over two hours, the film feels too long. I realize what a jerk I sound like making that complaint when I am watching a movie about people who avoided starvation in the frozen mountains by eating their dead friends, but there you go. They were up there for 72 days; I'm stuck in the screening room for 125 minutes and I'm whining.

But here's the thing! The film guide says the movie is 113 minutes, and let me tell you, there is nothing worse for a Sundance-goer than a movie that turns out to be longer than advertised. You plan your schedule very carefully, and sometimes you decide against a particular title specifically because the running time does not suit your needs. When it goes longer than expected, we get antsy and fidgety and frustrated.

On the other hand, when a movie comes up shorter than the film guide said it would be, it is a miraculous and joyful event. We dance merrily out of the screening room on those occasions. I'm sure I've given a few films better grades than they deserved solely for that reason.