It's A Wonderful Life (1946), is one of the most popular and heartwarming films ever made by director Frank Capra. Frank Capra regarded this film as his own personal favorite - it was also James Stewart's favorite of all his feature films.  The film's screenplay was based on "The Greatest Gift," an original short story first written on a Christmas card by Philip Van Doren Stern.
The story is actually a dark, bittersweet post-war tale of a savings-and-loan manager who struggles against a greedy banker and his own self-doubting nature in a small town. Earnest do-gooder George Bailey (James Stewart) recognizes his life as wonderful and truly rich, even in its humdrum and bleak nature, only after suffering many hardships, mishaps and fateful trials.  He is given encouragement by a whimsical, endearing, trainee-angel named Clarence (Henry Travers).
The story turns Dickensian (similar to A Christmas Carol, although told from Bob Cratchit's point-of-view rather than from Scrooge's) when the hysterical, despairing, and melancholy family man is shown what the small town would be like without him. It's a frightening, nightmarish, view of the world (at Christmas-time) that brings him back from self-destruction. He returns to the idyllic, small-town world that he left, with renewed faith and confidence in life itself. Hence, the film's title: It's a Wonderful Life.