Sacrificial fire and its attendant pain has many spiritual connotations. A funeral pyre suggests burning up or consuming that which is no longer spiritually necessary to us. A burning bush signifies divine knowledge imparted with passion. To be burning rubbish signifies getting rid of concepts and ideas for which we no longer have any use. When we are burning books, we are perhaps being judgemental in our appreciation of knowledge and information. A burning building signifies that we are putting an end to a particular way of life. To burn a boat suggests cutting off a means of escape. You might like to consult the entries for Fire and Light.