Another Elementary moment...
Okay, the M episode features Sherlock catching up with the individual he believes murdered Irene Adler, and he's quite prepared to torture the guy to death--only a plot twist stops him. We'll leave Sherlock aside for the moment, because what I really like is the reaction of Captain Gregson to the incident: he's furious, and does not even try to "understand" where Sherlock is coming from. He understands, all right, and in the next episode he straight-up tells Sherlock that imagining hideous vengeance is totally cool, but actually trying to do it is wrong and will always be wrong, no matter what kind of a monster Sherlock insists he's dealing with.
I was reminded both of Flashpoint, and also of a great speech by Ben Stone, in the early days of Law & Order: "The law does not just protect nice people!"
Gregson is immovable on this point. He expresses disgust and disappointment with Sherlock, tells him he can't trust him anymore, and even when he lets Sherlock come back to work Gregson refuses to pretend everything (anything?) is okay. I loved him for that. I've expressed before how much I hate the vigilantes-who-answer-to-a-Higher-Law (which is, of course, their own subjective interpretation of what is right in that minute) trope, and I hate them a lot worse when they're part of a system that is supposed to be impartial. Sherlock giving in to his own worst impulses under great pressure is bad, but at least the guy whose job it is to protect everyone else from caprice is up to the task. So Captain Gregson for the win, all the way.
The episode ends with Sherlock, who's been talking all episode about turning a small tortoise named Clyde into soup (I kept telling myself he was kidding), sitting at the kitchen table eating a bowl of something. Joan walks in and asks quite seriously, "Is that Clyde?" Sherlock picks Clyde up from the chair beside himself, plops him on the table, and asks, "You didn't really think I'd eat him, did you?" "Well," says Joan, "I never know, with you." And then she goes to bed, leaving Sherlock eating his soup and visibly reflecting on, and disturbed by, what he's done to a couple of relationships he values, and possibly also what he's been made to face about himself.
I missed the next few episodes last season so I don't know how this thread continues to play out, except that I seem to recall repaired relations by the end of the season. So I hope this is another thread in the continuing socialization of Sherlock, and that, having developed some actual positive relationships, he realizes he doesn't like the feeling of throwing them away. If that is the case, I give this show all the wins for letting us continue to like and root for Sherlock, while at the same time not coddling or condoning his behaviour in that incident. Fingers crossed.