Ceremony is necessary for the health of the community. It allows us to connect on a meaningful level with each other. We aren't sitting about talking, and we aren't at church, observing the ritual. We are part of it.
A ceremony doesn't happen while you watch, it happens with you, to you, around you. It makes you part of something deeper and higher than yourself. A ceremony requires you to slip free of your normal persona, and acknowledge a new way of observing the world around you. To take part in a ceremony is to catch a glimpse of your piece of reality, and to change it, when necessary.
The spirits are all around us. A ceremony is a way to honor their aid in your development, and also a way to ask for aid if you need it. In a tribal culture, ceremony is one of the very few hinges of the social structure surrounding us. The others are the elders, the chieftain, the warriors, the shaman, and the individual family.
Our way of life is about service to the spirits, the earth, and each other. Most of all, ceremony is a way to reaffirm that connection.