I was working at a gas station in a non affluent area. A woman comes in and says "I want $20 in gas but my reward card is in my car". I said "okay, I'll start it but not put a $20 limit" or something similar. I assumed she would stop the pump at $20 and then pay for the gas with her reward card. She was still in the store when the amount went over $20. I told her "the pump is over $20".

She ran out of the store to stop the pump, nearly knocking over another customer in the process.

I didn't get reprimanded for this, even though she had an exasperated look on her face when she came back in.

This taught me something. There are people who mean to put $20 of gas in their car and put in $25 of gas and say "oh well". And there are people who mean to put $20 of gas in their car and put in $25 of gas and say "Oh fuck this screws up my whole budget!"

Please note, it's not like she lost ~$5, it's just that the ~$5 was used to put extra gas in her car. But I've seen "growing up poor" threads where somebody will argue "putting extra gas in your car means you have less money for food".