I know what I must do. It's just... I'm afraid to do it
Of the three main characters in Lord of the Rings, this one is definitely the most relatable. That doesn't make him better than Aragorn or Gandalf, but it did make him easier to connect with the audience, at least for the first movie. He was the fish out of water protagonist that is commonly found in stories like this. And since he is unfamiliar with the issues of the outside world, when the other characters explain it to him, they are also explaining it to the audience as well. He is much like Luke in that when we first see him, he isn't anything all that special, he isn't a warrior or a genius, he isn't even that strong or brave. But circumstances force him to make decisions that he wouldn't have made on any other day and next thing you know, he is on a journey that will either change the course of his life forever or end it altogether. The main difference between the two stories is that there was really a point where we thought that Frodo might not make it out of this. In Two Towers, we really see the effect that both the ring and the long journey have had on him. His skin has lost its color, he is growing weaker and he's starting to loose it a little bit. By the time he finally reaches Mordor in Return of the King, he practically looks like a walking corpse. The thing that I love about these movies is that you really get the feeling that everything is on the line here, and that's not just the case with Frodo, if you watch the build up to some of the battle scenes like Helm's Deep or Minas Tirith, there is a moment where you basically realize that everything is on the table, and if they loose tonight, then that's it for them. Of course Frodo was carrying one of the most powerful objects in existence around his neck, so you can see why the stakes may be a little high for him.