As popular as it may be today to proclaim everything to be relative, that is not true. There is a right and wrong which transcend our society and our culture - and which remain right and wrong even in spite of our culture's denial.
Gerard Reed illustrates this well (in the Inroduction to his book C. S. Lewis Explores Vice and Virtue, Beacon Hill Press, Kansas City, MO, 2001) by citing a scene from C. S. Lewis' novel That Hideous Strength where the main character Mark, a young sociologist, encounters Bill Hingest, an elderly chemist. Mark suggested to Hingest "I suppose there are two views about everything?" to which Hingest replies "Eh? Two views? There are about a dozen views about everything until you know the answer. Then there's never more than one."
As long as we use feelings and emotions to determine right and wrong, the line demarcating one from the other is free to move. Only when we look to an external source (such as the Bible) can we have a fixed point to measure from. Until then, all our attempts to be "good" will depend on finding someone who tells us what we want to hear about ourselves.