Some cats are shy whether because of an early traumatic experience or the lack of socialization. Shy cats can make wonderful companions but you have to treat them carefully so they’ll eventually learn to trust you.
One key to dealing with a shy cat is routine and quiet. The less hectic activity around a shy cat, the less threatened it will feel. The more predictable its routine, the more it will trust its surroundings. Take time to coax a shy cat out with toys and treats and you’ll find that even the shyest cat can become a wonderful companion.