Must Read: "The Cop" the New Yorker's feature piece on Darren Wilson, former Ferguson Police Officer

I think this key passage from this long feature sums up quite a bit:
“I am really simple in the way that I look at life,” Wilson said. “What happened to my great-grandfather is not happening to me. I can’t base my actions off what happened to him.” Wilson said that police officers didn’t have the luxury of dwelling on the past. “We can’t fix in thirty minutes what happened thirty years ago,” he said. “We have to fix what’s happening now. That’s my job as a police officer. I’m not going to delve into people’s life-long history and figure out why they’re feeling a certain way, in a certain moment.” He added, “I’m not a psychologist.”

http://www.newyorker.com/magazine/2015/08/10/the-cop