From the book "Conversations with Archimandrite Ephraim, the hegumen of Vatopedi monastery on Mount Athos".
Secretiveness is another thing you should pay attention to. This is the greatest weapon of the devil. A secretive monk, who has secret thoughts and sins, may go as far as to schizophrenia. Do not conceal anything! It is especially important for naturally shy people to remember it. The monk has to overcome himself and this very shyness. This would mean that he completely gave all his heart to God. And if the person does not disembosom himself, even due to his shyness, the devil will beat him like an octopus.