China Holds Grudges

China holds grudges for long periods of times. Not only that, they use the past actions of other countries against them. I simply picture China as a child who wants something from their parents. Here's a fun dialogue of China being the child and some random country being the parents:
Mom: Wang I will not buy you a new math book!
Child: But remember when you threw away my old notebook by accident?
Mom: It was an accident and you don't need more math books!
Child: it was my favorite notebook and it's only fair you buy me an expensive math book!

Alternate endings

Mom: Fine,whatever heres an advanced math textbook.

Or

Mom: GTFO

Mao was a complete tyrant when he ruled. He created his vision of China through nondiplomatic means, but instead used force and deception. He would kill those who opposed him and with the combination of paranoia and immense power you have one of the most ruthless rulers in history. His power and paranoia allowed him to gain and maintain power for awhile because it didn't allow anyone to catch up to him or oppose him.

Go against China would be like me fighting Nico...wouldn't work

The United States should be friends with China. The reason why is because the US is in debt with China and China is a very powerful country as well. It is also important to note that the US is royally messing up their relations with other countries. Causing a huge rift with China would not be an ideal move or situation that the US would like to be in because of the power China has. Another important aspect to factor in is that the US imports many products from China and the US also takes advantage of the cheap labor that China has to offer. Overall being stronger allies with China would benefit the US more than hurt it.