In Game of Thrones, season 1, episode 1, the three rangers go beyond the wall. It's the first time we ever see the white walkers, when they slaughter a ranger expedition. In the TV show, the young ranger, Will, is allowed to flee south, where he is captured as a deserter and executed by Lord Eddard Stark (remember him?). However, in the books, the older ranger, Gared, who had been back with the horses is the one who escapes death only to be executed by Lord Stark a few pages later.
It seems like such a trivial detail to change, but that is why it disturbed me so much. Why change it at all if it made so little difference?
I'm sure the reality is something simple like a contract change or difficulty with air travel, but I'm wondering if anyone knows the real reason.