It doesn't work for all people, though. Over the years I've roleplayed with people who were absolutely incapable of playing a character that wasn't an idealized version of how they saw themselves. Worse, in one case I was in a run with a woman who was not only incapable of roleplaying anything except the beautiful and wise elf druid/ranger, but could not seem to accept the idea that other players' characters weren't, somehow, just as much a reflection of who they were. As I was playing a fairly cruel chaotic evil character, she banned me from being in her house (she was the wife of the DM) because I was "a bad person".

So although RPGs can be a really useful practice for getting into the heads of characters, it won't work for everybody. Sadly, I expect that those people who just can't put themselves in the mindspace of a character unlike themselves, in the context of either a game or a story, are probably never going to excel at either.