The instant I determine a person is a liar I put distance between myself & them. Habitual liars tend to be the very same people who blame their troubles on anything & everything except themselves. If a person refuses to take responsibility for their failings or shortcomings, they'll never expend the effort to correct them. Very self-defeating attitude.

When you let people like that in your life, they ALWAYS stick the knife in your back - sometimes because it benefits them, other times because they simply enjoy tearing other people down. And if you adopt an aggressive philosophy of constant self-improvement & strive to better yourself, haters & parasites are drawn to you. That includes friends & family especially.

My 2 cents.