Ben Affleck should choose these sorts of roles more often. Here, he stars with Samuel L. Jackson in an amazingly powerful story about a chain of bad deeds. It shows how wildly out of control things can get when ordinarily nice people succumb to moments when good will is inconvenient, then again when they succumb to the temptation of petty revenge. This had to have been a hard story to pull off: for it to work, it is crucial that we are sympathetic to two characters who ultimately do horrible things. But this is precisely what happens, because we see these two characters in other contexts. We know them as they do not know each other, and we know that these are ordinary, fallible human beings inside.

The movie is a compelling story first and foremost, and it's was a very personally involving one for me. But it also inspires thought: how much trouble could have been avoided if, at any point after their first meeting, just one of them had broken the chain?

Here's another one: although the two characters practically self-destruct, note where they are at the end. It's easy for generally good people to slip into corruption bit by bit. The two characters are already part way there. But note what happens when the pace accelerates beyond their ability to justify their own actions to themselves.