A common retail scenario:
Cashier "4 gallons of organic, vegan, free-range lube....that'll be $18.73."
Customer "Oh, hold on a minute, I gots me some exact change. Um.....I gots a 50cent piece, a button, 3 nickels, um, oh wait, I've got a lot of pennies here to get rid of......"
"......um......ok, here's the 73cents!"
HOORAY! YOU MADE SOME EXACT MOTHERFUCKING CHANGE! May sweet baby Jesus anoint you with glory and accolades for such an auspicious event!
I know that most of us have worked crappy, cash-register centric retail jobs at one point or another, or work at one now, or will work at one in the future the next time the banks and politicians have another "Oooopsie! We done blowed up the economy again! Gimme a bailout!" episode. Here is a simple fact that should guide your actions when waiting in line to pay with actual American cash dollars.
Do not try to give exact change. Ever.
"But, but, but, but I've got a penny right here!" you might say.
Shut it. Keep it. Give it to a bum. Throw it away. Level a chair leg with it. Just keep it in your filthy pocket.
Why? Why am I being such a tyrannical towering turd about this?
99.999999% of the time, a customer will NEVER, EVER, EVER, EEEEEVVVVEEEERRRR be able to give exact change faster than the cashier is able to give the change back to you. Get it? You (yes you, yeah, really, you, numbnuts) are not exempt from this rule. I don't care if you're Rainman, or have coin-spewing machine lodged in your rectum. You will not beat the clock on this one. In fact, you will most likely be slow as hell, thus delaying the line, and significantly shorten the lives of those behind you who have the decency to pay via credit or debit card, or hand over cash and let the cashier make change, and of course, not take eons of time to write out a stupid check from the 1950's.