Dead Little Brother: Sort of; His little brother died at the age of 19, but although it may have made Yudkowsky's search for immortality more personal, he was already an atheist, immortalist and an advocate for cryonics before this tragic incident.
Part of the real reason that I wanted to run the original AI-Box Experiment, is that I thought I had an ability that I could never test in real life. Was I really making a sacrifice for my ethics, or just overestimating my own ability? The AI-Box Experiment let me test that.
The Singularity: He is convinced of a coming technological singularity is determined to help bring about a positive singularity regardless of the uncertainty of success.
In one sense, it's clear that we do not want to live the sort of lives that are depicted in most stories that human authors have written so far. Think of the truly great stories, the ones that have become legendary for being the very best of the best of their genre: The Iliad, Romeo and Juliet, The Godfather, Watchmen, Planescape: Torment, the second season of Buffy the Vampire Slayer, or that ending in Tsukihime. Is there a single story on the list that isn't tragic? Ordinarily, we prefer pleasure to pain, joy to sadness, and life to death. Yet it seems we prefer to empathize with hurting, sad, dead characters. Or stories about happier people aren't serious, aren't artistically great enough to be worthy of praise - but then why selectively praise stories containing unhappy people? Is there some hidden benefit to us in it? [...] You simply don't optimize a story the way you optimize a real life. The best story and the best life will be produced by different criteria.
...if you think you would totally wear that clown suit, then don't be too proud of that either! It just means that you need to make an effort in the opposite direction to avoid dissenting too easily.
Drugs Are Bad: Averted — Although Yudkowsky apparently doesn't want to try mind-altering drugs, he is in favor of drug legalization.