In short about sociopaths.
Fashion on them went because of a couple of films where such guys are allegedly represented. But as the main characters, they have strong positive traits that outweigh the negative. Aggression, greed, contempt for others, cowardice (yes, from self-love) and others are reduced by directors and authors to moderate values, which only adds charm to the heroes, making them more cynical.
In fact, sociopaths are geniuses. Most are truly sick people who are honestly (and fairly) considered to be ended muffles.
In the series, the sociopath of Cumberbatch-Holmes very sweetly despises Watson. A real...pat would have dropped the doctor in trouble, at least for the sake of indirect evidence. Or Lenny. He would not have understood what was so bad.
and short. Do not try to parody sociopaths - it will not work out, and the egoist in you (us) is seen without any effort. and ;))