An American in Provence

This morning, I stopped by La Poste to buy a stamp. I used the automatic machine, and as I was collecting my stamp and change, an elderly woman asked if I could help her to buy some stamps. Of course.
Here is our conversation.

(her)- I need three stamps. How much would that be?
(me) That depends on the weight.
- I NEED THREE STAMPS!
(louder) Okay, okay, that will be about 1.70 €.
- HOW MUCH?
(select three normal stamps) 1.74 € !!!
(she pulls out all the change in her change purse and tries to figure out how much to give me. There are two one-euro pieces, as well as various smaller coins)
- HOW MUCH?
Give me the two euros.
(she passes me one and puts the rest away, I put the one in the machine. Still need 0.74)
Please give me the other euro.
- I GAVE YOU TWO EUROS! What did you do with the other euro?
No ma'am. You just gave me one euro.
- You stole the other euro!
(she rummages in the machine and pulls out 10 cents that were left over from my transaction, which I hadn't had time to recover before she accosted me for help)
- Where are my stamps?
You need to put in the other euro.
- I don't have another euro.
Yes you do, it's in your purse.
(she took out the other euro (miraculously, in her purse) and puts it in. The machine prints out the three stamps, but then is slow in producing the change. I just walked away at this point. And no point in arguing that she in fact stole my ten cents. That would just be beyond her capabilities of understanding.)

Please God, let me still have most of my faculties when I am old.