This is because, whether or not our self-esteem is high, the pressure from the community's opinion still has us on invisible chains. But, for introverts, those chains are visible. Hence their crippling anxiety.
The law states what a citizen is, so consequently it will be the deciding party of what a good citizen is. The government and the public go about following the rules and regulations set by the law.
But few argue that the decision of who a good citizen is ultimately in the hands of the citizens themselves. They are the ones who decide what is required to be considered good and reasonable citizens.