This is similar to how we acquired our morals. These are directly affected by external factors that influence us to act or think accordingly. Among the three, emotion is the only thing that cannot be controlled or influenced by other things. Janice Ho, a psychologist, once said that although emotion is one of the most primitive taints left in man, it is also the most complex, since no man has ever gained total control of it before. (Ho, Janice, 236).
When it comes to justifying moral decisions, I believe that one must first consider if his/her morals is more important than what the society demands. If he/she gives more importance to the society's acceptance, this is the answer; although emotion cannot be avoided when deciding, reason is far more important. For instance, there are laws that seem "unlawful" because we find it unjust. We find it unjust because our emotions are against it. Take for instance the "One-child policy" in China, where children who are no longer wanted are freely aborted by their mothers. (Wang, Y.) Some people who find this unacceptable go completely against it. But, looking at the action of the mother from the law enforcer's view, what she did is right, since she complied with the laws, and that is reasonable (Huang, Gary).