Sherlock and John refer to the time Sherlock was pretending to be dead as his year Away. Privately, Sherlock calls it the Year in Hell. He survived it, but he came home changed, and not for the worst. He is still essentially himself, but he tries to remember that his friends don't always appreciate the purity of his deductions. His insights are not meant to be hurtful - well, not usually - but they are what he sees. Slowly, he's remembering to put a filter between his observations and his mouth.