I worked with a company once that makes QR code tags so people can quickly contact owners in case of a lost pet without exposing the owner's information along with receiving any necessary pet health info. It'd be way simpler if vets could just teach people how to use microchip + phone.

I struggled with how arbitrary things felt until I dove deeper into equal temperament and why our western music system is how it is. At the end of the day it's just a language and saying one or the other implies different info about context! youtu.be/bCYcS57eCqs?...

I'll throw in Natural Selection 2! I think it's one that few will name, but it does a lot of interesting things.