1. His Insensitivity Upon Returning Home To See John
Some of the examples on the list so far were just plain funny within the context of the show; the tactlessness, the smartassery and the complete negligence of social normality is part of what we love about Sherlock Holmes. He's a high-functioning sociopath: we can't expect him to be nice all the time. When Sherlock returned to London though to surprise John, he genuinely made himself the villain. Not content with simply crashing his meal with Mary a meal in which he was going to propose, by the way he had to do it impersonating a French waiter. He had to spring the news on him like that, didn't he? There was no prior warning whatsoever, but the worst part was that when he realised quite how heartless he'd been, he didn't care that much to stop there. He saw that it was one hell of a shock for his best friend, and he still made fun of his new moustache. That's just horrible: it's no wonder John beat him up for it. We love you Sherlock, but you so deserved that.
