Speaking of which, I come to recall one villain we fought, it was one of my old characters; when he was my character, he had the "mentor" mentality, always needing to teach people things, always getting frustrated when the INT 7 barbarian charged needlessly through clearly visible traps and needed to be healed, again.
Cue several months later, we end up in a campaign where monsters are learning tactics, and we end up almost getting tpk'd, at level 7, by goblins due to this. I had my suspicions.
We end up getting into the main room, and we are greeted by an animated statue with a prerecorded message. Also we were instantly locked in.
"You know, I used to be a teacher. Before I was a villain, I was an adventurer like you lot, and before that I taught. I taught that every man and woman needs to learn their duty and then some. Then, after my adventuring career was over, I taught that every man and woman need learn to defend themselves, need not be so helpless. And yet still, they ignore my teachings.
In the end, it's my... no, our fault, us adventurers and mercenaries. Allon (that was our old group leader) had a saying. 'We exist because there are the weak and they need protecting.' I recently learned that was backwards. The weak exist because we protect them. That must change. For the good of the weak, the weak must be culled, or grow strong. That is why I do what I do. I teach. I teach the people to not be weak, and I teach adventurers lessons as well. Lesson one, always assume that the villain has a tarrasque."
Just as the statue's speech ended, the backwall of the room crumbled to the tune of a charging tarrasque, and we had to roll initiative.
That was a fun session.