So, let's imagine you are walking down the street drinking a box of tea. You finish drinking the tea. Now, what do you do with the box? Do you drop it on the ground? Or, do you do the right thing and drop it in a trash can? Hopefully, you drop it in the trash can because, besides harming the environment, littering is also very impolite. Recently, a magazine published a list of the most polite cities in the world. They looked three things: did people litter, did shop clerks say thank you and did people hold the door open for the person behind them? The top three politest cities were New York, USA, Zurich, Switzerland, and Toronto, Canada. Hong Kong, China was number 35. Shanghai wasn't even on the list. Does that mean that Shanghai is not a polite city? Well, maybe. There are different ways to judge  politeness but the survey was looking at how a visitor to a city would feel when walking around its public places. Visitors don't like to step over empty tea boxes as they walk down the street. They don't like it when they buy something and the shop clerk doesn't say thank you or even give them a smile. They also don't like it when someone lets a door slam  into them instead of holding it open. Shanghai is a nice city but it is not always the most polite city. I don't think this is intentional . I think it's just a lack of awareness . China is becoming a popular place for tourists to visit. When they come to Shanghai they will find a friendly city: it would be nice if they also found a polite one. And, remember, being polite makes you feel good, too. It's nice to be nice. The writer mainly wants to tell us   _  .
not to drink tea in the street to hold the door open for anybody to remember to be polite in public places to travel to the most polite cities more often