My 3 year old DS is very shy around people who are not family. He is usually a very outgoing, smart, funny kid at home. When we go places and I ask him to say hi to a person, or do something like play in a group, he won't do it even when he says that it looks fun. I'm trying to teach him what manners are, and it's so tough when he refuses to do it. He is strong willed to say the least. What do I do?