Don't know why, but I've often thought about lying.
Not a specific act, but the concept itself. In particular, one question has percolated in my head over the years; What is the most effective kind of lie.
I've come up with many answers, lies that contain a hint of truth, lies that are mostly true, lies that are 100% true, but imply falsehood... (you may notice a pattern, lol)
All good answers, but there's one particular genre of lie that beats them all:
The lie you tell yourself.
Think about it folks, who can lie to you more effectively, more enticingly, who knows what you want to hear to believe something better than you yourself?
Obviously self deception is dangerous in and of itself, but once you've convinced yourself of a falsehood, it becomes easier to convince others, because the sincerity of your words compels others to believe what you say is true.
Something to chew on.
The first time I really chewed over this phenomenon is when I heard it said of Tony Blair, from politicians who knew him, that he was somebody who could convince himself of anything. When you combine this with a manipulative personality who selectively - even if unconsciously - picks the truths he wants to believe and pass on to others, you get a master manipulator.