I remember reading back in 2014 (IIRC) Yudkowsky's explanation of the Bayes theorem. It was genuinely good. Some sort of first principles introduction.

HPMOR was entertaining as well. Death as the last enemy to be destroyed placed his priorities where his mouth is.

For a brief time back then I used to visit Lesswrong and many comments including Yudkowsky's were plain stupid (which was not hard to reason at all) but coming from folks who valued themselves as first principles thinkers was an oxymoron.

But his timeless equations (IIRC), Bayes theorem explanation and HPMOR were all remarkable and I will always appreciate those works.

My favorite writing of his is:

https://www.yudkowsky.net/rational/virtues