Sacrifice keeps the tenuous balance between the human world and the divine realm intact, assures that the dramatic vagaries of divine dissatisfaction will be held in check. In the Roman context, where sacrifice serves as a first line of defense in the preservation of political stability, the refusal to sacrifice or the perversion of the carefully balanced sacrificial relations produces threatening seismic fissures running underneath the foundations of society.
“The pervasively public nature of religion meant that Christian withdrawal from ritual events could not readily be hidden. Faith in 'God' in the NT was by no means simply a particular devotion to this deity or a belief that one held as a private religious opinion. The uniqueness of the NT 'God' was to be matched by an exclusivity in the devotional behavior of believers. Their devotion to 'God' required believers to disassociate or distance themselves from core activities of their cultures, especially the worship of the gods on whom the welfare of city and empire was thought to depend. That is, faith in the NT God involved both a 'cognitive dissonance,' and also an unavoidable social dissonance (which could, and as time went on, did involve sometimes severe dissonance with political authorities). As noted already, philosophers of the time toyed with various ideas about the gods with impunity (e.g., whether they were all one or whether some of them had been invented) in the cosy and safe settings of their elite circles. These were little more than thought experiments with little substance and of no major impact on the religious practice of these philosophers or of people more widely. Early Christian faith in 'God,' however, involved a much more robust 'atheism' in beliefs and religious practice!”—God in New Testament Theology, pages 30-31
So much for private spirituality, eh? The life of a Christian should be at a dissonance with the surrounding culture. If it isn't then something is wrong...