The world is horrible. The more stiffening the outcome, the greater the possibility it is of being likely. In a sense, people already know the answers when they are asking for truth, they just want to hear it spoken. Usually when lying, anyone can make you, some just lie to themselves for their own benefit. When anyone lies, it is selfish, and promotes self-benefit.
People lie for money, sex, and power mostly.
A giant race to get all 3 at once. Lying is just a boost of nitrous, sure, it can help for the time being, but will fuck you up in the end. Lying is usually brought upon by insecurity. Lies are told as an improvision to make up for shortcomings that the liar might experience. If they cannot face up to a situation, they will lie in attempts to save themselves.