100 people will give you 120 answers

Is that though not likely to be the case in any society or group of people? Granted there are a few things that we could probably agree to as being universally the 'right/wrong thing to do' like not running over cute kittens with a monster truck and helping little old ladies cross the road but by definition a value is only given importance by the individual and different individuals have different values.

As for your girl who told you 'I have no principles', isn't saying that 'I don't follow a code' in fact an admittance of having values by which to live your life. People in the past have termed this 'counterculture' - peace man!