Happiness is the by product of decision making. And, the decision making is driven by consciousness which is of two kinds. One is inner and other is external consciouness. The external consciouness is awakened form and is moved by sensory organs. The sensors collects the data, collate it into information and influence our decision making. This is imitative in nature and can be sometime deceptive. Whereas the inner consciouness is instinctive and subtle form and is independent of sensory organs. Therefore this is pure in nature and cant be adulterated.
Both the consciousness coexist in every human. Every decision making has influence of either of them which gets reflected on the outcome. Therefore happiness is the outcome of decision making which is more influenced by inner consciouness. The outward sensory organs are always inclined towards comfort & convenience which amplify unhappiness.
You will agree with me that, there is a subtle inner voice in every individual which always warns the person before committing something wrong. W
hether we listen to this voice or not, is a different matter. If you remember the first time you would have bribed someone, hands might have been trembling, legs would have been shivering. The simplistic explanation of this - one is going against inner consciouness or sailing from purity to impurity. This inner consciouness has subtle voice which says - look, you are doing something wrong.
The difference between demon and devil is to listen and act or ignore the inner voice. Our sages has always pursued the awakening the inner consciousness Thats the reason we are called as seekers. To go inwards and awakened the inner consciousness and be happy.