What's the most valuable thing you can learn in an hour?

A lot of what hackers do takes years of building knowledge upon knowledge. That’s also true for physicists, marketers, salespeople, managers, etc. Are there any quick wins that 30 ~ 60 minutes of intense concentration can generate?

For example an average person, if focused, can learn to read (but not understand) Korean decently in under an hour. A person can also learn a few guitar chords and possibly play a carefully-chosen song in that time.

But those aren’t valuable skills in themselves.

Do you know of any simple + valuable wins in your area of interest?