One thing I will never, ever be able to comprehend as a cashier is why customers cannot place their money to pay in our outstretched hands. Despite recent controversy, my favorite thing is NOT to pick up your scattered exact changed from the conveyor belt.
If you are the customer that flings your $20 dollar bill at me for your $19.98 dollars worth of groceries, yells at me to keep the change and the leaves the receipt I just handed to you floating upon the floor, I have nightmares about customers like you. Oh, and your two cents? HUGE dent in my bank account, so thanks.