How to treat people who quickly "change their faces"?

Have you ever heard of changing your face in one second? If you haven't heard of it, you should know what it means after reading these words, so I won't explain it to you.

On the Internet, I saw my face changing for the first time on Weibo. At that time, there were two groups of pictures saying that the face changed quickly. The first set of pictures shows the doctor smiling at a place at first. He should have his own patients. However, as soon as I turned around after I walked over, that smiling face immediately turned into a cold face, which surprised me at the speed at which people changed their faces. I forgot what the second set of pictures was drawn, so I won't talk about it.

But some people say that it is impossible to change your face so quickly in real life, but you really think too much. Such people do exist in real life.

I went to the hospital once when I was sick. At that time, the doctor was really gentle and enthusiastic, and gave me the feeling of being a relative, explaining a lot of pathology and how to treat it. But I paid the medical bill, and the doctor immediately changed his face and ignored me. What makes me feel faster is that I think running every day is too much trouble. I asked the doctor to cook all the medicines for me, and I took them back together. When I went to get the medicine the next day, the doctor was still smiling, but as soon as I heard that I wanted to take all the medicine back, I stopped doing those useless tests and immediately became like an enemy. The little nurse who gave medicine threw it directly on the table for me. Later, the doctor felt a little too much and treated me a little better. Let me prescribe two more western medicines, and the attitude is that you won't tell me what medicine to take unless you buy it in the hospital. I was drunk, too. I suddenly remembered going to the hospital in high school, the doctor who told me that the medicine in the hospital was expensive and asked me to go out to buy medicine.

In fact, I also know that every industry has moths, so I don't comment much. Just a piece of advice, sometimes, especially when renting a house, don't give money first, let the landlord clean up the house before giving money, or you will know the speed of the tornado.