Insecure
Phobiactic.
Because they are afraid
a wuss
The midnight society.
a big baby
a fear or phobia
From what I understand there is no specific phobia for people who are afraid of mail. Most just call it Mail Phobia...
People may be afraid to be themselves due to fear of rejection, judgment, or not fitting in with societal expectations. Society's emphasis on conformity and the fear of being vulnerable can also contribute to individuals feeling hesitant to show their true selves.
outspoken?
nahh
Conversing with oneself is known as self-talk or inner dialogue. It is a common behavior that can help organize thoughts, problem-solve, or provide emotional support.
causality is when someone or a pet may be themselves without being afraid.