This movie is very different from the ones Hollywood churns out every year. The theme itself is so unique and radical, that the movie is worth watching for just that reason. There are more reasons too.
Cast Away is no doubt dominated by a central character, who gets stranded on an island. The man who made this movie has a great insight into human mind and its working. Its a pretty unusual situation that is portrayed -- which is why not many people can relate to the movie well. The hero gets stranded in a pacific island, all alone. Not a single human being or even animal to talk to.
The agony of this man is portrayed exceedingly well. His first reaction and hope of escape, and how slowly he settles down to his life there. His acquiring skills which only necessity teaches a man. He goes to the very basics, like making fire by rubbing wood, fishing in the most primitive way etc. Very interesting watch, if you can bear the slightly slow pace at which it moves.
Not the typical kind of hollywood movie that one expects to watch. If one goes with this in mind, all should be well. The movie goes on, till our guy plans to escape from the island after 5 long years. Of course, there are lot more details, but I am leaving them out.
Eminently watchable.