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Honestly, Sherlock didn't expect John's angry reaction at his return. He was doing what the doctor had asked for after all.
Yes, he had left him thinking that the sleuth was dead all the while.
Yes, he'd let him think that he wanted to die that day by not making use of his wings. Thank God anger made John choke on his words so he hadn't actually mentioned his wings explicitly or that would have been hard to explain to his fiancée and curious bystanders. What came out was more of a, "You didn't even try to..."
Yes, he'd let him think that John had pushed him into it. (...Wait, no. He hadn't. How had John gleaned as much from his actions? He had never meant for John to believe such a horrid thing.)
The main point was that Sherlock had reasons for his actions, very sound too, but that apparently didn't matter. John didn't want to see him, or talk to him, or have anything to do with him, and even if Mary promised that she'd make him see reason (Sherlock didn't want to owe John's presence in his life to his friend's attempt to please a woman – that never happened before) what if she couldn't?
If Sherlock had lost John forever – well, he would have lost John much more definitely if he hadn't acted like he had – so maybe he had to lose John anyway. (No, destiny didn't exist, now he was just being silly.) He wasn't worthy of his friendship, that was for sure, so it all made sense in a warped way.
But it hurt, God how it hurt. Sherlock spent hours on the sofa, hugging himself with his wings, a perfect cocoon of misery, praying that John would come in and just exist in his immediate vicinity.
It was lucky chance that he was dressed when Mary came instead, and then there was no time to wonder why a nurse would know a skip code at first glance. There was only John, who was very much not safe despite everything Sherlock had done, John who might die and die angry at him and maybe Sherlock had died too, and this was hell. It would make sense.
Especially because they were burning John and this was what Moriarty had promised to do, but Moriarty was dead and this had all to be a horrific nightmare. And even if it was a nightmare, John had to be okay or Sherlock was going to make his nest in these flames until they consumed him, too. But luckily John was alive, so the sleuth had to leave him to his fiancée and paramedics and anyone John didn't hate now.
Though apparently saving people's life meant they were on speaking terms with you again. (The whole fall had been about saving John's life, why couldn't the man see that?) And even that they'd come on cases again. The world was finally starting to right itself once again. If he could have one cup of John's tea next he wouldn't be wanting for anything. (Lie. He'll always want John in 221B. He'll always want these few perfect months of his life back. But he couldn't ask for the impossible. He didn't deserve it anyway.)
When he'd seen the chance, he'd exploited it unabashedly. Either John forgave him or he was left to die alone (if so...it'd be a pity to disappoint John once again). And John forgave him. Better yet, John laughed with him. So they went back to 221B and had tea and Sherlock stripped (back against the wall) so he could spread his wings and feel John's eyes on them. Nobody looked at them quite like John did, with awe and affection and conveying, "So beautiful," even without a word.
And today, once again (without asking this time – almost as if not realizing himself what he was doing, entirely entranced), John had caressed his quills. Again and again and again. Probably simply to enjoy the solidity of them – their undeniable existence – but it absolutely stole Sherlock's breath. He wanted it to go on forever. He needed this to stop now, before he made a fool of himself, before the gentle touch triggered something that would disgust John.
When he moved away from John's light caress – maybe more sharply than necessary, but doing so needed quite a lot of effort on his part – John looked surprised and then immediately flustered. "I'm sorry...I didn't mean...I didn't hurt you, did I?"
"No, I...I just..." Christ why was his mind empty of excuses? The dopamine had made him stupid. The truth, then. "They're...sensitive. In a good way."
John flushed the most brilliant red. "Oh god. Sorry. I didn't know. I didn't want to -"
"I know you didn't. That's why I stopped you," Sherlock replied. Why did this hurt? It wasn't supposed to hurt. As John never stopped pointing out, they weren't – like that. Maybe it was only the knowledge that John would surely keep a respectable distance from his wings now. He wouldn't get to casually brush his quills against John anymore, would he? Stupid, Sherlock.