One major disadvantage of being shy is that you find it difficult to talk strangers, thus making new friends becomes a challenge and don't even get started on approaching a woman (or a man) that you are interested in.

I have few friends who are super shy and socially awkward and when people ask them questions, everytime they transfer to a new school, they just smile creeping and hope questioner go away and hence they always end up being the loner. Though they like it that way to have their own personal space, they can read quietly and can eat alone in peace"