"You cannot do wrong and feel right. It is impossible." 

-Ezra T. Benson 

If you do bad you will feel regret afterwards. You can try your very best to fake that you are okay with the action you committed but deep down you'll feel guilt and that is not okay. If you always choose the right, you ll never feel this way. If you were to cheat on the person you supposedly loved, you would feel horrible. You would do anything to hide this from him/her and make sure she/he  never finds out. But why cheat in the first place ? Why chose the wrong over right if it doesn't bring you anything good ? When you chose the wrong, all the that comes after it is repercussions.