Sherlock trying to figure out what John wants
Why is Sherlock surprised that John is leaving, here, at the end of the shooting the happy face domestic?
The most literal reading says Sherlock doesn't, 'get people'. He's rude and inconsiderate, immature.
Sherlock has been reading John's blog. The blog shows that John likes him and he's happy about that. It also seems to be a bit insulting to him and he doesn't like that.
John is expressing his feelings and impressions on his blog. Greatly in part, his feelings and impression about Sherlock. I think Sherlock figures that, therefore, he would like it if he talked to him about his own feelings: open up to him.
He's been stewing at home thinking about all their mixed messages and why John is still dating Sarah. He's decided that when John comes home he will talk to him.
He lays down on the couch almost as if he were at therapy. He loves John, he thinks John wants to talk about feelings, he talks.
*Sherlock brings up John's blog*.
To Sherlock it's obvious that some of John's comments on his blog were offensive and insensitive. He wants to talk about that because he's clearly very sensitive but since John already sees him as unfeeling, he doesn't understand why sherlock is offended. He chalks it up to Sherlock's ego, I think. It's not until Sally laughs at him when they talk about the blog that I think it hits him that this was hurtful and embarrassing for Sherlock,
Sherlock opens up, like he thinks John would want him to but, instead of being happy, John leaves. This is exactly why he's been sad and now that he's done what he thought John wanted John left. From Sherlock's point of view, this doesn't make sense,
This face says it all, 'I'd kiss you but you're a jerk: I'm leaving',
If we think back on all of John's kiss-related enacting, aka all his, 'kissy faces', we will see that a lot of them occur at a time when John is mad at Sherlock. John is attracted to Sherlock when Sherlock is being a jerk. Sherlock realises this and therefore acts like a jerk. Much like how the, 'enough with the cheekbones', comment only activates maximum cheekbone power from Sherlock. AKA Sherlock is always trying to be attractive to John.
Later in TGG, John will have a one-sided argument with Sherlock about caring. Sherlock, now, will be emotionally impenetrable. Hiding his feelings comes easily to him, he admits. We can gather from this that his earlier talk with John was difficult for him, it was him making an effort to connect. And it blew up in his face. For all we know, he was up all night working up the courage to talk to John. John left him, again, and his flat literally blew up,
But, when he's cold, machine-like Sherlock, John does not leave. He stays, he accepts it. They move on and go work on a case. This is how you keep John Watson around, apparently,
From this Sherlock concludes that this is actually what John likes: he likes cold, aloof Sherlock, though he thinks he would like him to open up, when he does he rejects him.
Sherlock is too inexperienced with sharing feelings to know that it wasn't his opening up that John didn't like, it was his approach. He really was too blunt and too rude to John. But, Sherlock only knows he made an effort, he made himself vulnerable, isn't that what people do?
This is like when he brigns up Sholto, John questions him on why and he says, 'chatting'. Then, gets an odd look from John and says, 'won't be doing that again'. Or when he makes a joke about Dr Mortimer and John tells him, 'funny doesn't suit you. I'd stick to ice'. No wonder he says, 'thank you', at the stag night when John calls him funny. He's probably remembered that, 'stick to ice', comment ever since.
John sends him a message to be more human and then, when he is more human, he sometimes gets the message that he shouldn't be.
When John figures out that Sherlock and Mycroft have a sibling rivalry, he says, 'nice... now we're getting somewhere'. But, this is a tidbit that John finds out for himself, from observing Sherlock being cold. John wants to see throughout the façade for himself. I think that he's drawn to the cold exterior and wants to chip away at it. But, when Sherlock exposes what's inside he often has a reaction that makes Sherlock feel like he needn't've bothered.
I think this push-and-pull has to do with John's own lack of readiness to be with Sherlock and his reluctance to get hurt. He makes himself vulnerable right off the bat at Angelo's and gets shut down, royally. After that he feels constantly vulnerable, like he's the one that put his cards on the table and Sherlock has the power of never having done that.
But, to Sherlock, he has done that, again and again. He's asked him on a date, lent him his bank card, given him cheques for his work, written a romantic cypher on their wall, opened up about his feelings, etc. In Sherlock's mind, he's put himself out there with everything he's got and he's still getting what to him is a hot-and-cold John.
By the time they argue about Sherlock having no feelings in TGG, Sherlock has decided to be unfeeling because it's WHAT JOHN LIKES. This way John doesn't leave him. John is attracted to his harsh persona, after all. And only wants to find humanity in him himself, not when Sherlock shows him. Sherlock is John's mystery and he doesn't want any clues. He wants to solve Sherlock all by himself.
This is why Sherlock continues to be, 'a machine'. It's for John. Because that's whom he has concluded John loves.
