“Do you ask me what you should regard as especially to be avoided? I say, crowds.”
Being the introvert I am, this answer from Seneca (letter 7) received from me a warm welcome and strong affirmation. However, I quickly learned that his reasoning was not formed from a fear of crowds or a feeling of discomfort one might experience in a room full of people. Instead, Seneca issued his warning against the crowd for the harm it imposes upon one’s soul.