The best armour of old age is a well spent life perfecting it. - Charlie Munger

Which models are the most reliable? Well, obviously, the models that come from hard science and engineering are the most reliable models on this earth. And engineering quality control — at least the guts of it that matters to you and me and people who are not professional engineers — is very much based on the elementary mathematics of Fermat and Pascal: It costs so much, and you get so much less likelihood of it breaking if you spend this much. It’s all elementary high school mathematics.

I didn't get to where I am by going after mediocre opportunities.

There is nothing more counterproductive than envy. Someone in the world will always be better than you. Of all the sins, envy is easily the worst, because you can't even haven any fun with it. It's a total net loss.