Everyone can live their own truth or whatever, but spend enough time alive and you start to notice personality traits that people can't stand. We could all gain something from spending our time around less manipulative or abusive people. See, the problem with people who lie a lot is that you can't really ever confirm or get them to admit that they're being manipulative. It's one of the things that keeps them from being found out. Ask a liar if they lie and they'll just lie some more. That's why it's important to simply know the signs so that you can come to that conclusion without going through the arduous process of making them admit something negative about themselves. Because remember, they won't. The only way to win is to not play the game.
At the same time, if we see ourselves doing these things it's a good chance to know if we're alienating our friends and coworkers. It's important to acknowledge yourself slipping into this kind of behavior, because people will actually tolerate it. That is, until they wise up and stop talking to you. We can dodge a lot of bullets by knowing what signs to look for in red flags for roommates or red flags at job interviews.