Sorry for this belated reply, @possiblyimbiassed. Keeping up with what’s going on here is still an exhausting affair for me, so I haven’t caught up with all the comments to this post yet. Yours (both this one and your other comment) somehow just got lost in the comment tsunami.:)
“[…] Culverton doesn’t actually confess to any particular murder or other crime in TLD, he just says that “killing human beings” makes him “incredibly happy””
That’s a very, very important point you’re making there, I think.
We probably all agree by now that the metaphor Mofftiss have been employing over and over again is: MURDER = FALLING IN LOVE, right?
So, what Culverton (=John!mirror) gives us here is a deeply interesting insight into John’s personality.
Granted there are people who experience no trouble whatsoever in being single for a prolonged period of time. Some people really don’t mind living without romantic love for years or even decades. But John most definitely isn’t one of them. John needs love. John needs to be in love. He needs it like the air that he breathes.
What’s particularly interesting is the fact that this trait of John’s, in and of itself, has nothing to do with Sherlock specifically.
As you’ve observed quite correctly in your comment, Culverton doesn’t even tell us that it’s Sherlock he wants to ‘kill’ (=love) specifically.
My guess is that this is because, Sherlock or no Sherlock, John has always been this way. That’s who John is. John needs to be in love. And originally this had nothing to do with Sherlock. It’s a character trait of John’s. John needs to be in love to be happy. It’s a deeply ingrained part of John’s nature. It’s his personality. He’s always been like this.
(Well…Obviously, once John meets Sherlock, this need to love is directed full force at Sherlock. He finds in Sherlock, the perfect receptacle for this love of which he has always had a lot to share.)
But it’s not Sherlock who has caused John to be like this. John has always felt the need to have love in his life. If he hadn’t met Sherlock, he would have kept endlessly falling in and out of love with men and women alike. It’s just that with Sherlock he has finally found THE one person.
I really think that’s what Culverton’s (John’s) confession means. That’s why Culverton doesn’t tell us that he needs to ‘kill’ Sherlock specifically. John’s nature is to love people. Not all people, obviously. But to be in a relationship with someone is what John needs to be happy. This is who he is. Sherlock or no Sherlock. That’s what he’s always been like.
Or to be more precise, it’s what Sherlock has worked out John is like (!). Because a lot of us (myself included – and you have written some of the most brilliant meta on the subject –) don’t believe anything in s4 is ‘real’. It’s all Sherlock’s dream/coma/imaginings/hallucinations or whatever. In short, it’s all Sherlock’s EMP.
So, in other words: This isn’t John speaking. It’s Sherlock working out what John’s confession might be all about: John is confessing that he always needed love and still needs it. He has always been a ‘serial killer’ (ie, a serial monogamist). That’s what John’s nature is like…is what Sherlock is telling himself (!) in his own mind here.
But why doesn’t Culverton tell us he wants to kill Sherlock specifically?
As you rightly observed, “[…] But not even then does he tell Sherlock that he wants to kill him[…]”
Because it’s all in Sherlock’s mind!
It shows us how deeply repressed Sherlock actually is. He can’t bring himself to even just think, “John actually really wants me.” Not even through the thick veil of a murder=love metaphor. Not even while employing a Culverton=John mirror.
In Sherlock’s mind, Culverton never says, “I want to kill you,” because Sherlock can’t bring himself to think, “John wants me.”
What Sherlock does instead is all the more heart-breaking: He tells Culverton (aka John) what HE (Sherlock!) wants!
He tells Culverton (=John) that he wants Culverton (=John) to kill (=love) him. That’s the only thing Sherlock dares to think at this point. “John, I want you to love me.” But he doesn’t dare to think it the other way around. (“John wants me.”) Or at least he doesn’t spell it out yet.
Oh, boy, the amount of things those two don’t dare to say to each other or even just think about each other…Just wow!
In your other comment, you stated that ‘Did you miss me?’ is less compromising than ‘I love you.’ While that is true on some level. I sometimes wonder if maybe ‘Did you miss me?’ isn’t even ‘worse’ in a lot of ways.
I mean, I can totally see myself say, “I love you, man,” to a buddy of mine without it being romantic in any way. Well, it depends on the tone, I suppose. But you can totally say that in a “Bro, I love ya,” kinda way. (Not meaning to imply that Sherlock and John’s confession would be that kind of thing, obviously.)
But seriously, honestly, genuinely asking another man, “Did you miss me?”…erm, nope! I wouldn’t pull that with anyone but my better half. If I were to do that with just any (male) friend I can think of I would probably be asked, “Are you feeling okay, sage? What’s with the emo mood today?”:D