Your conscience is what tells you whether an action is right or wrong. It is the reason you have guilt or remorse after doing something morally questionable, and the reason you feel relief or pride after telling the truth or giving to charity. It can also have an affect on decisions you are contemplating. If you just have a bad feeling about a possible action, your conscience may be telling you to choose otherwise. The sense of right and wrong is learned and deeply embedded, so someone with a very strict religious upbringing may have a more critical conscience than someone brought up with a looser moral compass.