Family is important because, when everyone else has, in a way, excluded you from being a human, you can count on your family to except you no matter what. If you are bad to your family members they might exclude you from the family, which might be good for them but will probably be bad for you.
It is important to spend time with your family because, well, it's your family. Spending time with your family can strengthen your connection with the rest of the family, it can also help you learn about yourself and who you are.
The adding of people to your family can, in most cases, be very good. In most cases parents will choose to have or adopt a child which is adding a member to the family... or in other cases you can consider a person part of your family without them being related to you in any way at all.
The excluding of people from your family can be good if the family member does not treat the rest of the family well, but can be bad if you are forced into making the decision of excluding a member without the willingness to do so. So when adding or excluding a member to the family make sure it will benefit the family.
