My personal belief is that family environment is the most important factor in shaping adult behavior. This come only from my own observations; some people think the peer group is more important. After all kids spend more time at school, and around their peers, than their parents. As far as things like drug use that might be true; but not for overall mental state.
Other kids affect your life but at the end of the day you go home and are around much bigger people who determine your complete lifestyle, sustenance and safety. You need their approval for survival. The ultimate social group, in which one must learn how to adapt and fit in, is the family.
As advocates of alpha behavior have sometimes admitted, alpha behavior is not always adaptive. In any group there is only one alpha and challenging him or her is dangerous. Control can be maintained through disapproval as well as violence; disapproval can take all kinds of forms.
If the parents are highly neurotic the child may maintain a very closed, unexpressive front to avoid disturbing their delicate psychological constitutions. This same kind of very guarded personality is very off-putting in other social environments. If the person is used to feeling threatened, and regards other people as threatening, he won’t be able to drop his guard. If he does, his behavior will be goofy because he’s not used to modulating his behavior to the social environment.
The closed, guarded personality is one way of avoiding threatening social interaction. Another strategy is clownish behavior. This says, “I want to be liked and interact with people, but at the same time I’m not to be taken seriously.” Something similar would be exaggerated niceness.
The second two seem obviously submissive, but is the first? After all, avoiding emotional interaction doesn’t directly imply one is beneath another. However, humans are emotional, social creatures and to block out this kind of interaction implies it is threatening to oneself. Part of successfully interacting with others is gaging the correct amount and type of emotional content to include in the interaction. The degree of serious or light-heartedness; the degree of friendliness or distance; and the degree of sociality are all elements of this.
In general people who are adept at social interaction are socially valued over those who are not. The first school of social interaction is the family. A positive environment and success here are the best first steps to success later in life.
People who don’t learn good social interaction skills as children can learn later in life, but it will be a fairly long and involved process.