The following is a viewing diary I wrote as I watched the show for the first time, pausing after each episode to collect my thoughts. As such, it is spoiler-free for upcoming episodes (although the comments section may not be).
This is certainly the darkest episode of True Detective and also very likely the best. There are no brutal murders, mutilated corpses, bloody crime scenes. The darkness is inside and when it manifests itself in violence it only goes so far as a fistfight. But when Hart and Cohle pummel each other in a parking lot, their punches land with more force than all the gunfire of five episodes.
We begin with two scenes that could easily be played for righteous catharsis, but are delivered as something else entirely. First, Hart confronts the two young men who were caught having sex with his daughter. He offers them a choice: allow him to beat the shit out of them or go to prison on statutory rape charges. Of course it isn't really a choice at all - he doesn't want his daughter's sex life made public and he would very much like to punish these two himself. It's many fathers' vengeful dream come true, yet this interaction is scored and shot without any sense of deliverance. The following scene contains the biggest surprise: before he can drive off in triumph, Hart vomits all over the parking lot (the same lot in which he and Cohle will fight a far more evenly-matched bout).