One thing about sherlock that I love is how he is often perceived as someone who doesn't care. But the thing is, his problem isn't that he doesn't care, it's that he CARES TOO MUCH. He feels too much. His heightened senses, don't you think the only way to live with them is to sometimes shut off those feelings. As an autistic person, what I feel is often that I am incapable of understanding people and their emotions, but I feel them. Their fear, their worries, their sadness, and I feel it, I experience it, sometimes more than I do my own. Don't you think someone like Sherlock, who is aware of so much, feels it too? He may not understand it, but he feels it.
And when he does care, he cares with everything he's got. He doesn't just like Joan, he feels so many things from admiration to worry to love, and so often his love for Joan is too much.
When he allows himself to, and when it's the right person, he loves with all his heart immediately. He allowed himself to love Jamie and despite how short they knew each other, it was so much. Even after everything that's happened, he cares so deeply and strongly that it takes up the whole room. Not in-universe, but through the screen.
And he loves unconventionally.
And he cares and he cares and he CARES so much, and "he's rude" and "he's not nice", but when he thought he was talking to a victim of child abuse, there was more care and precision and empathy in his voice than most others have in their hearts.
"He's rude" "He's not nice" "this is sensitive he shouldn't be here", but no one as calm and empathetic and dedicated to be non-threatening as Sherlock on his knees when they free a trafficked woman.
Maybe one reason he decides to try and not care, to pretend that there is no warmer, kinder him waiting to be coaxed out into the light, that he can be cruel and that is what he is, to the bottom, is that feeling this much all the time would not just hinder his work, it would disable him more than maybe anything else in his life.
