 And since real world accidents almost always have multiple causes, other phenomena such as groupthink can also be occurring at the same time.In particular, it is a mark of a dysfunctional organization to simply blame the last person who touched something.In 2012 Charles Perrow wrote, "A normal accident [system accident] is where everyone tries very hard to play safe, but unexpected interaction of two or more failures (because of interactive complexity), causes a cascade of failures (because of tight coupling)."