Why do people lie?

It was Tad Williams who said, “We tell lies when we are afraid… afraid of what we don’t know, afraid of what others will think, afraid of what will be found out about us. But every time we tell a lie, the thing that we fear grows stronger.” People can be so afraid of what might happen if they told the truth. Maybe they have done something wrong and are afraid of the consequences of their actions, so they lie to cover up what they did. As is often said about political scandals: It’s not the crime that gets you in trouble, nearly as much as the cover-up.

Do you believe in lies for goodness?
Is white lies okay?
How do you react to someone who confesses that he lied to you after you fully trust him?