<VV> Dr. Jack, counter help

[Alan and Clare Wesson]

>> I gave the girl a $20. The beer was $3.75, so I gave her another quarter 
>> and asked her for the bills back. After a solid three minutes of getting 
>> puzzled looks, I asked Chico what 20 take away 4 is. He immediately gave 
>> the answer, and I told the girl to just five me back $16.

Yes, as JR has pointed out, she must have thought you were completely mad. 
Some weird old guy with a kid comes in, orders something that costs $3.75, 
gives her a $20 bill, and then gives her another 25 cents (so that she now 
has a total of $20.25), and demands $16 back instead of the $16.50 he was 
due. Giving her the extra 25 cents actually made the math *harder* for her.

Perhaps she thought you were trying to give her a 50 cent tip, although it 
sounds as if your attitude at the time wasn't symptomatic of this...

Cheers

Alan