There are no leaves...

Everyone writes about customers, I write about the seller.
I had to buy a regular thermometer for home use. Looking out the window and making sure that in the courtyard of the 21st century, it was decided to buy an electronic instead of mercury.
I go to the pharmacy and ask:
I: Do you have gradients?
Seller: (with the face of deepest regret) No, it’s all over...
I: (Sorry, but I do this based on life experience) There are absolutely no, neither mercury nor electronics?
Seller: Absolutely, all bought out, in the city an epidemic.
I: (I was already leaving) And how much did they cost?
Seller: Mercury - so much, and electronic (does half the turnover on the chair, gets the thermometer packed from the shelf, and under my stinking eye, calls it the price from the price list).
It is the half of trouble that the seller and the ear did not blink, there was more.
I lacked the electronic money. I asked what time they worked, the good lived in 5 minutes. I went home, took the necessary number of paper rectangles and went back to the pharmacy. I repeat, it all took from 5 to 10 minutes.
I: Please sell me an electronic thermometer.
There are no shops, we bought them all.
I: (I'm a stinker, ticking my finger on the box where the thermometer came from) You have a thermometer, sell it to me, please.
Seller: (As nothing happened) Yes, please He sells me a thermometer.

How is it possible...