I used to work in the candy store/gift shop of a family summer camp. It is hard to explain without giving away the location or name. Families would come for a week at a time and the store was attached to the dining hall so it was open around meal times. Most of the time I was working alone which meant running the cash register, keeping the store straight, and helping customers all at once.
At the end of one week it was busy which is normal because everyone wants to buy souvenirs and get their last candy fix. This means I have a constant line at the register and leaving to help customers means the line just builds up.
This woman comes in and wants to get her child a reward for being good during the week which is fine except the deal was that he would get 100 lemon heads which are individually wrapped. First of all, this is ridiculous as in my opinion, if this is what this kid needs to behave, he is not going to have fun later in life. Secondly she insists that she can just estimate what 100 lemon heads look like to save me time. No way that is happening.
I have no idea what 100 lemon heads look like and even if I did, I make a big deal about being exact with sales and not short changing people or letting them get more than they paid for. So I had to sit there for a few minutes counting out 100 of these things which doesn't sound like a long time but keep in mind no one is at the register while this is happening, so all the other customers waiting are getting frustrated.
Finally I deal with this customer and begin grinding through customers to try to get the line at the register to a reasonable length.
Next time buy him a candy bar.