How do we know what is right or wrong? Is it ultimately what we read or what we feel in our gut? every individual is different and feels subjective about what is right and wrong. Our society values individuality, so what really binds our collective consciousness?
Determining the criteria for good/bad, right/wrong is the fundamental concern of Ethics. I couldn't possibly give you a coherent answer on this forum since this fundamental question is still an ongoing issue in philosophy today, as it has been for the past 2600 years in the history of western philosophy.
Some, like David Hume, have argued that morality is nothing but a gut feeling or "sentiment." Others, like the early Greek Sophists, argued that morality is simply the interests of the individual and does not adhere to any universal standard.
However, the majority of the wisdom traditions concur, that there are a set of universal standards that apply to all in the same manner, regardless of particular individual desires or beliefs, e.g. Plato, Aristotle, Kant, Mill.
You might want to take a look at Plato's Republic (at least the first two books of the Republic) for an interesting introductory discussion of the possibilities.