Every child is different, and each has their own personality.I think while it's good to stretch our kids to be more open to new situations, we also need to allow them to be confident in their own skin.My almost 5-yo daughter takes a longer time to warm up in any new room - even if she has been in that particular room weekly for the past 2 years. Once she's comfortable, she becomes a little more warm, but it's unlikely for her voice to be heard. With new people, she'll stare off in the middle distance and not engage, even when the new people are all gushing over her. In our home though, hers is the loudest voice, many times telling her brothers what to do etc.She is most unlike our outgoing boys (who can be counted upon to shake hands and greet new people - even strangers on the MRT!), but we attribute it more to her personality than be concern about the manner in which she engages new people in outside environments.We do talk to her about what is expected behaviours; that she needs to greet our friends and relations, that she needs to ask for permission for doing things in a formal environment etc, but where the behaviour stems from personality, we are fine with taking a step to allow her to be in her own comfort zone.After all, there are many adults who are introverted or extroverted, and each personality takes their energy in the way they engage with their environment.