Why are some boys friendly and polite, but they are always alone and don't even feel his existence?

This shows that this boy is relatively low-key in both doing things and being a man, and is cautious in words and deeds. But such people are not necessarily withdrawn and don't like making friends. On the contrary, such people may be better at observing things, have rich and delicate feelings, and know how to care for the human body and stick to people. Therefore, people should know more about each other, especially those who are different from themselves, and should be polite and respectful!