So, a neat thing about the current design philosophy about pocket knives is they wanna be fun to fidget with, that you wanna flip them open and closed on your own idly whenever you're bored. The idea is that if you work their action for fun when you're bored then you'll just sorta passively ingrain the neural pathways for deploying the blade so that when it's time to actually use it, you'll already have the muscle memory to do so effortlessly.
I am extremely intrigued by that sorta concept. The idea of designing around unstructured play and fun as a way to hone practical, if extremely specific, skills. I'm imagining a society designed around play for that reason, that what you find inherently, kinetically, stimulating is used to passively build a practical skill in people just by the inherent design of things.