If the Northeasters are all descendants of people who traveled to Shandong and Hebei, why is there such a big difference between the Northeasters and the Shandong people now?

My friend, your understanding is somewhat inaccurate.

There are indeed many descendants of Shandong and Hebei in the three northeastern provinces, but compared with the aborigines in the three northeastern provinces, education and customs are not the mainstream, so for generations, customs and culture have influenced each other to form this situation.

Moreover, there are differences in customs and educational habits in Northeast China. For example, there are many Korean settlements and Manchu settlements in Jilin Province. People in these places are all from the northeast, but do you think their habits and temper will be the same as those of the Han people in Hebei?

Moreover, for example, the United States used to be a British colony, and British immigrants were the main body, but now there is not much difference in personality and habits between Americans and Britons in these areas.

Personally, the formation of a person's personality is mainly related to the growth environment, and other factors can only affect part of it.

As far as population distribution is concerned, it is formed according to the local mainstream social education and customs.

It is said that one side of the soil and water will support one side.