There is a moment late in the film, after the two main characters have been slugging it out with each other for an entire day, when Gavin Banek (Ben Affleck) pauses for a speach. He tells the story of a day at the beach, when you find yourself standing next to a beautiful woman. Somehow, you know deep down in your soul that if you would only talk to this girl, she'd go home with you and your entire life would be different. But you don't, and she doesn't. And you spend the rest of your life wondering what might have been.

Banek's point is that this day, filled to the bursting point with one bad choice after another, is like that day at the beach. For the rest of his life, Banek will look back on this day as his turning point, his "what if."

This is what makes Changing Lanes such a poignant exercise in character exploration. Every single one of us has a moment like this somewhere in our past, some more than one. Hopefully none of them are as severe as the events in the film, but because each of us occasionally asks what if, we are able to relate to these characters, even if their choices are extreme.

The film begins with two men in dire need of arriving to court on time. Gavin Banek is part of a prestigious law firm that has just been entrusted with the multi-million dollar foundation of a recently deceased client. He only needs to present the paperwork to the court. Doyle Gipson (Samuel L. Jackson), meanwhile, is in the midst of a divorce and must appear in court if he wants any chance of continuing to be a part of his children's lives. Gipson is a recovering alcoholic with a proven history of unstability.

The two have the misfortune of running into each other on the freeway. While exchanging information, Banek becomes impatient and offers to write a check to Gipson for his wrecked car rather than wait for the police. Intending to establish that he can do the right thing, Gipson refuses and demands to handle the accident correctly. With a shrug of "better luck next time," Banek hops in his car and drives off, leaving Gipson stranded on the side of the road with no way to get to court on time.

Unfortunately for Banek, he discovers that in his haste, he left an essential part of his paperwork behind at the accident. Gipson recovers the file and realizes that he now has a position of power over Banek. Facing the loss of his wife and kids, he decides to extract a little revenge against the lawyer for leaving the scene of the accident. Banek, in turn, retaliates by tampering with Gipson's personal files and credit ratings.

Had this film been simply a display of two men trying to one-up each other, it would have been boring and heartless. Furthermore, it could easily have generated into a tale of fastastical revenge scenarios possible only in a film. Instead, Changing Lanes remains grounded more or less in reality, with both men striking out well within their means. What makes this film interesting, and very successful as a thriller, is that for each wrong step the characters take, you can see them struggling not to take it. These are two men who have let their emotions overrule their judgement.

The casting of Ben Affleck and Samuel L. Jackson is dead on. Jackson can always be counted on, but it was Affleck that surprised me here. He's certainly a competent actor, but for this film he does something interesting. There is a perception of Affleck as the sort of kid who breezes through life, always getting the right breaks and stepping above those with more skill through the judicious use of charm and the knack for being the right place at the right time. Whether intentional or not, Affleck plays with this perception in Changing Lanes. He plays the sort of character who finds himself in a position at a high-profile lawfirm without any real idea how he got there. He's in over his head and somewhere deep inside, he knows it. We meet him on the day it all comes crashing down, when his charm fails him and he realizes that, perhaps for the first time in his life, he's actually going ot have to work to get by.

The writing and directing is also first-rate. I'm sure there was pressure to create this film in a more traditionally Hollywood style and refreshingly, that pressure was resisted. Changing Lanes has been crafted as the best sort of thriller, where every twist in the plot has the audience cringing, knowing exactly what the characters should be doing and eagerly watching as they don't do it.