After a second watch, I put my finger on what upsets me the most in that episode: my Johnlock feelings are hurt! Nah, but seriously, just not think slash here, just friendship, and it's just the same.
In the previous seasons, I really enjoyed how John, little by little, made Sherlock a bit more "human". Even if Sherlock remained clumsy and tactless when it came to relationships (which gives him a part of his charm, really), you could clearly notice he was improving at John's through contact with John and I thought it was a good thing.
I have no difficulty to understand he is unstable after two years on his own. We know that deep inside, he's not as cold as he seems to be, and we know he cares more for John, Mycroft, Mrs Hudson, Molly, Lestrade... that he would like to admit. Therefore, even if "caring is not an advantage", I find it hard to imagine Sherlock putting everything behind it that easily. Of course he was perfectly fine on his own, but then he experienced life with John and discovered what the word "friendship" meant.
I'm one of the people who think Sherlock was far more dependent on John than John was on him. So I'm pretty sure he missed John during those two years and that John hasn't been the only one to grieve.
He also has his pride (we know how much he cares about what people think of his work and of his capacities) and I guess it must have been hell for him to have his reputation ruined (even though he was then cleared), to be dead for the rest of the world, to stay in the "shadow", not to solve crimes with John & the police anymore... etc ect. That's what John implies at the end when he says Sherlock has missed being Sherlock Holmes.
And then we don't know what happened during those two years but he certainly wasn't on a Bora Bora beach with feet up. We have a glimpse of what his every day life must have been at the beginning of the episode. Not a picnic, huh.
So yeah, no wonder he comes back quite different.
After a first watch, I thought his reunion with John in such a light tone, with him disguised as a waiter and thinking he was funny was really really cruel. If my husband, who killed himself in 2012, suddenly makes such a come back, believe me, I would be far less "indulgent" than John. As much as I would have loved a hug between them (all hope is not lost for later, though, hehe), John's reaction was to be expected. I really disliked Sherlock when he did that.
But then, after the second watch, I thought it was probably the best reunion I could have hoped for. Sherlock is so tactless we couldn't expect more from him. And I actually find his clumsiness in that scene quite endearing to be honest (again, not if I were John!). He had expected John to have put his life on standby just because he was dead/gone and he probably expected him to throw himself into his arms.
I would give a lot to know what's going on in Sherlock's head when John reacts in such a different way than the one he was expecting.
Anyway, my point is that even though I unconsciously hoped he would have "matured" during his time away, it's only fair he has kinda "regressed".
But then, why is he like this with John when he's getting all sentimental (that's a bit exaggerated but then we're talking about Sherlock, not about "normal" people, lol) with Molly and Mycroft? I mean, playing games with Mycroft when he used to be annoyed by his simple presence? And those kind things he tells Molly and that kiss on the cheek? Yes, it's not the first time, but in SIB, he only gave her a kiss because of John giving him a dark look. There, no one is telling him what's good or bad, he's doing nice things spontaneously.
I'm not saying he is incapable of being nice, it just annoys me that he is kind to other people but not to John. I know that being a die-hard Johnlocker, I'm a bit biaised about this, but still, even I think of them as just friends, I still think the same.
It still would have been ok if there hadn't been that train scene at the end. That mockery. Yes, it sounds like Sherlock to do such a bad joke. Yes, he's done this before. Yes, he never learns his lesson. Yes.And no I wouldn't have minded such a scene in the second or third episode, but just after their reunion? Just when John is only starting to overcome the shock and the feeling of deception? Seriously? Even for the tactless asshole Sherlock can be, that was utterly cruel and John truly is a good sort.
Coming back different, "regressed", ok. But I would have hoped he would have softened again through the contact of the one he used to consider his only friend. But maybe it's just me...
I'm glad there is that final exchange when he tells John "I heard you", and they look at each other, and then Sherlock lowers his eyes and changes the subject. I like to think he is quite touched at this moment. But who knows? He's Sherlock, after all...