A curious horror overtook him, then. His skin crawled; the back of his neck turned damp and cold. I can’t go… — Charles Stross

Intelligence and infinite knowledge were not, it seemed, compatible with stable human existence.

“Will you stop calling me a child!”

Rachel hunched around in her chair and stared at him. “But you are, you know. Even if you were sixty years old, you’d still be a child to me. As long as you expect someone or something else to take responsibility for you, you’re a child. You could fuck your way through every brothel in New Prague, and you’d still be an overgrown schoolboy.” She looked at him sadly. “What would you call a parent who never let their children grow up? That’s what we think of your government.”

Time travel destabilizes history.

History is a child of contingency; so many events depend on critical misunderstandings or transient encounters that even the apocryphal butterfly’s wing is apt to stir up a storm in short order.