Where Do I Get Ideas?

A novel is only as good as its ideas. So where do I get mine? Since I write historical fiction I read a lot and select the juiciest true stories for my fruit salad of a novel.
For example, one of the worst Nazi interrogators was Klaus Barbie. I read a cold blooded incident where he took a cat into the interrogation room, where a terrified citizen waited. Barbie stroked the cat with soothing words, seeming nothing like his reputation. He handed the cat to a guard in the hall and gave the prisoner a glass of water with a sympathetic word. As the thirsty prisoner raised the glass to her thirsty lips, Barbie swung his meaty hand at her face, propelling the drinking glass to the other side of the cell where it shattered. He stood and screamed, towering over the citizen, demanding answers to his questions.
That story was so compelling I adapted it and included it in my story.