Liars like to lie, and you often see them express what's called "duper's delight" at fooling people. Dark triad types (narcissists, sociopaths, psychopaths) will often lie about petty things just to get off on their ability to mislead people.

It's also a form of gaslighting. It makes people doubt their sanity, because nobody would lie about such a thing. It creates an aura of reality distortion around such people and inside that aura they can define reality as they see fit.

Until we learn to see through this stuff and stop elevating such people to positions of extreme power, we deserve what we get.

Unfortunately there’s a pretty large number of people who actually think we need people like this to “do things.” It’s a self fulfilling prophecy. If you stack the ranks of power with dark triad types, then of course that’s the only kind of person who can work in that world. You create a world where only toxic people can get things done and then are surprised that only toxic people can get things done.