honest to a fault..

Dear customers,
It is NOT helpful when after I ring in your order you try to "help" me by giving me more change to make an even number...let me repeat NOT helpful.
I am an arts student plus my generation grew up with calculators, therefore...I don't do math.
If you gave me the rest of my life I will still not be able to figure out what change I owe you now that you have complicated things. The machine will tell me what to give you, and I don't think a few pennies will kill you.
Not only do you make me feel like an idiot, but you hold up the line.