Another confused american here.

I really don't see the difference between a yard & a meter - they're both an arbitrary length of measurement even if a meter is the distance traveled by a ray of electromagnetic (EM) energy through a vacuum in 1/299,792,458 (3.33564095 x 10-9) of a second. 'cause seriously... how fast EM energy travels through a vacuum has no bearing in my life and it means nothing to me.

A yard might be an old term, but it's fairly easy to remember that it's the distance if you put your arms between them. A foot is about the length of a foot, and an inch is about what it is between your thumb knuckle & the first joint.

Now I will grant you that doing things on a base 10 scale as opposed to 12 inches in a foot, 3 feet in a yard, is a lot easier to remember.

But I can approximate distances in yards, feet, inches fairly easily given those handy body part approximations.

Another scientist - so in the lab I'm completely used to nanoliters, microliters, etc. etc. and I'm definitely glad I never have to do that in nanoounces or something. And I probably couldn't if I tried - however, at home in the kitchen cooking, it's handy knowing, add a tablespoon of sugar and even if I don't have an actual measuring set, I can go grab a tablespoon or tea spoon or tea cup and get close enough to what the recipe is asking for. If a recipe asked for 300 mls of solution - other than with a pipette or graduated cylinder, I have no idea how much 300 mls is. Okay, a soda can is 355 ml, so I might be able to grab one of those and use it to measure.