I suppose I love this movie because one of the main themes of the film is that we all make a difference in the lives of others, even if we don't realize it. In other words, we all have a purpose.
In the movie, George Bailey (played by Jimmy Stewart) is a depressed, frustrated young business man who is never able to chase his dreams. He feels trapped and feels that his life is a waste. When he finds out that his company (a savings and loan) is short a large sum of money (due to an error on his uncle's part), he realizes that he would be better off dead than alive. His life insurance money would more than cover the deficit.
Clarence, George's guardian angel visits him and shows George what life would be like had he not been born. It takes George a little while before he realizes he truly has had a wonderful life and that others have been greatly impacted because of his presence in their lives. He realizes the truth of his situation and he decides he wants to live again regardless of the circumstances.
God hears that prayer and he rushes home to find the bank examiner and the police waiting for him to arrest him. He says to the policeman, a friend of his, "And I'll bet that's a warrant for my arrest, isn't that wonderful!"
This reminded me of the apostle Paul who, while in prison, told us to "Rejoice in the Lord always! I will say it again: Rejoice!" (Philippians 4:4)
How could he say that while in prison? Because he had a new perspective. Just like George Bailey, he was shown what was truly important. As a result, his tough circumstances didn't really matter.
I am not saying this because I am in need, for I have learned to be content whatever the circumstances. Philippians 4:11