An exceptional narcissist may even create mental spaces where their lies can be experienced as unfading memories. A simple mindset shift could open up new worlds of ready information.

Another type of trouble is with those who don't allow themselves to know they're lying. If they know it, they vaguely feel a hint that they're doing something wrong, but consider it justified, and ban the memory from existence by removing all strips of its perceived value. If they have that level of self-awareness to begin with.

Can't be reasonable with someone who firmly believes they can never be in the wrong.