God created some as very social and others more introverted. Even looking at the animal kingdom you see the same. For example the prairie dog is a very social creature while the rabbit is not. The prairie dog lives in communities of its own kind and does not leave its young, quite unlike the rabbit. With people some are born people pleasers and others more quiet and they stick to themselves. Oftentimes more social personalities make poor evangelists due to their often people pleasing nature of always wanting to keep the peace and not offend anyone while more introverted types will say it like it is. I believe being introverted and not as social is not sin and part of Gods design. The chapter on the body of Christ (Romans 13) confirms that not everyone is the same.