I guess I'll share my own story.
A friend of mine made a comment about how he'd rather take $15 in pennies than in $1 bills when I owed him for lunch, so I decided to pay my local bank branch for a withdrawal.
I forgot why, but I also needed some $5 bills, so I get up to the teller, swipe my card, and tell her I want $50. $15 in pennies, the rest in 5's. So she opens her drawer and only has a few rolls of pennies, so she goes and grabs one of their bank bins full of rolls and counts out 30 rolls. So far so good! She asks if I want a bag or something for the pennies and I say sure. She then goes rummaging around in some cabinets until she comes up with a faux leather bag.
After concluding the penny business, she reaches back into her drawer, grabs a stack of $5 bills and hands me one.
I'm standing there a little confused until I finally tell her that I withdrew $50. She stares at me for a few seconds before saying "Oh! You're right." So she grabs the stack of $5's again and counts me out a total of $50 in 5's.
So now we're in an awkward stand off. Her, thinking that my transaction has been concluded. Me, thinking this teller is totally distracted by my level of attractiveness and wasn't so bad herself and I could probably ask her out if I wasn't married.
So I finally say that this isn't right either. She gets embarrassed and says she normally knows how to do math, but she obviously doesn't know what to do. So I give her a few more seconds before I tell her to give me $35, seven $5 bills. She does the math in her head for a little bit and says yeah, $35. Then she gives me the correct amount of bills and asks if I want a paper receipt. I say sorry, I'm married, and walk away.