Pretty much all of my evil characters.
The party inevitably killed them.
Now, this never happened because my evil characters dissed the party in any way.
It's just that they couldn't stand my evil characters. MY idea of EVIL characters is just too way out.
For example, we came into the town to buy supplies.
My evil fighter/mage bought the goods from the shopkeeper. Then, she killed him for her own amusement. Then, she tortured and killed the next shopkeeper. Then, she burned both establishments down, enjoying the mess. She thought it would be interesting to burn down the whole town, assuming the party had the power to do so, but was gravely disappointed to hear they did not have such might.