Sergei

“So Harry was going to leave this problem to Fred and George, and they would discuss all the aspects of it and brainstorm anything they thought might be remotely relevant. And they shouldn't try to come up with an actual solution until they'd finished doing that, unless of course they did happen to randomly think of something awesome, in which case they could write it down for afterward and then go back to thinking. And he didn't want to hear back from them about any so-called failures to think of anything for at least a week. Some people spent decades trying to think of things.”
― Eliezer Yudkowsky, Harry Potter and the Methods of Rationality

“Twenty years later, that was what he would desperately wish had happened twenty years ago, and twenty years before twenty years later happened to be right now. Altering the distant past was easy, you just had to think of it at the right time.”
― Eliezer Yudkowsky, Harry Potter and the Methods of Rationality

“Everyone thinks they’ve won the Magical Belief Lottery. Everyone thinks they more or less have a handle on things, that they, as opposed to the billions who disagree with them, have somehow lucked into the one true belief system.”
― R. Scott Bakker, Neuropath

“Harry's thoughts flashed back to possibly the worst moment of his life to date, those long seconds of blood-freezing horror beneath the Hat, when he thought he'd already failed. He'd wished then to fall back just a few minutes in time and change something, anything before it was too late...

And then it had turned out to not be too late after all.

Wish granted.

You couldn't change history. But you could get it right to start with. Do something differently the first time around.

This whole business with seeking Slytherin's secrets... seemed an awful lot like the sort of thing where, years later, you would look back and say, 'And that was where it all started going wrong.'

And he would wish desperately for the ability to fall back through time and make a different choice...

Wish granted. Now what?”
― Eliezer Yudkowsky, Harry Potter and the Methods of Rationality