Follow-up to: Boring Advice Repository
Many practical problems in instrumental rationality appear to be wide open. Two I've been annoyed by recently are "what should I eat?" and "how should I exercise?" However, some appear to be more or less solved. For example, various mnemonic techniques like memory palaces, along with spaced repetition, seem to more or less solve the problem of memorization.
I would like people to use this thread to post other examples of solved problems in instrumental rationality. I'm pretty sure you all collectively know good examples; there's a comment I can't find from a user who said something like "taking a flattering photograph of yourself is a solved problem," and it's likely that there are other useful examples like this that aren't common knowledge. Err on the side of posting solutions which may not be universal but are still likely to be helpful to many people.
(This thread is allowed to not be boring! Go wild!)
Remember that BMI is based on the total body mass, and that muscle is denser than fat. (OTOH, that study corrected for level of exercise, and it's quite possible that the BMI that would maximize an average white American man's attractiveness if he's not allowed to vary his level of exercise would indeed be around 20.)
I am one of those “many”, too, but ISTM that in present-day Western cultures we're a minority; "thin" seems to have become a compliment. (Last year, someone offered to set me up with her roommate who probably had BMI around 18, and when I told her that I didn't fancy her, she retorted “but she's so skinny!” as though it was a positive.)
Ah, good points.