This is a movie with no heroes, no nudity, no CGI and practically no fancy stunts, yet somehow it manages to hold your interest.
After feeling genuine hatred for the two lead characters, more so for Banek (Affleck) than Gipson (Jackson), I found that the ending wrapped up too quickly, too conveniently and too smoothly, and while it was reasonably watchable the first time, I probably wouldn't want to see it a second time.
Both Affleck and Jackson play their parts convincingly, and make it almost believable that a fender bender could lead to such chaos. In the real world however, Banek should have wised up to his work situation from the beginning, and Gipson would have certainly fallen off the wagon. Personally, I could never be charitable to a man who purposely sets out to destroy my family's chance for happiness, or lies about my kids safety, which makes the somewhat neat ending leave a bad taste in my mouth.
The bankruptcy story thread was unconvincing. The highly paid professional just accepting his failure with a shrug off is just not realistic. There are other parts of the movie where the lead characters cause significant damage to office property without repercussions, and some of the support actors tenuously cling to the storyline like afterthoughts.
Considering that this movie is about greed, arrogance, despair, revenge, deceit and blackmail, it does very well to maintain a reasonable entertainment value. The "positive message" comes too late to be of significant redeeming value.
Jackson's performance carries the movie as far as it can go.