This Reddit thread asks what a person can learn in 10 minutes that will be useful for life, and the top-voted answer is using your hand span, thumb to pinky, as a built-in measuring tool. Mine is 7 inches, which I will never forget now.

The other favorites in the thread are worth sharing for your relationships and your nervous system: “Never explain yourself to people committed to misunderstanding you.” Before responding in an argument, scan your body and take a slow nasal breath to notice fight or flight before you speak. Then speak calmly. “‘No, I can’t’ is a full sentence. You don’t owe anyone a 10-minute TED Talk about why.”