The human body is a product of this material world. The material world that we live in is basically composed of the three modes of material nature - The mode of Goodness, The mode of Passion and The mode of Ignorance. As the living entity at the time of birth comes into this material world it comes in contact with these three modes of nature and gets conditioned by them automatically. The five elements - Earth, fire, air, water and ether, its properties are also a mixture of these three modes or having one of them more than the other in there nature. For example, fire is influenced by the mode of passion more than compared to ignorance and goodness, Earth can be said to be influenced by the mode of goodness, water by the mode of goodness and passion, ether under the mode of passion and ignorance. At times these elements are also influenced by different variations of these modes. As per vedic scriptures also this human body is made up of these five elements.
Because the living entity gets conditioned at the time of birth by these three modes, he started believing in dualities that arise from these three modes and dualities lead to anxieties. The three modes forcefully make the living entity perform actions either in goodness, passion or ignorance or evil deeds. And hence the living entity keeps shifting his actions between good, passionate or evil. Obviously being entangled under the influence of these three modes the living entity is either happy or sad as per the fruit of performed action which keeps changing all the time but the living entity is never happy all the time and hence never in peace all the time. Its obvious, everything moving and non moving and its outcome is bound to happen as per the will of God. But the living entity divided the result of his actions (the result which was given by God as his will) into two groups namely- happy and sorrow. These words were created by living entities.
Its obvious, performance of actions under the influence of these materialistic terms - Good, passionate or evil actions, one will either experience happiness or distress in different times and in different walks of life but one will never be happy and peaceful all the time. Observe properly if you can, that when you performed good deeds and other times when you did something out of passion and deep desire or at some other times when you hurt someone out of anger, greed for your own benefit, sometimes you experienced happiness and other times anxiety or distress. So the idea is don't stick to these material feelings - being good or passionate or angry or greed etc for performance of your actions. Only do it because it ought to be done as a duty. You will realize you are already in the mode of happiness, not material happiness but blissful happiness.Transcending these three modes by remaining in God consciousness destroys the two illusionary groups made by us - Happiness and Sorrow in which we are entangled since time immemorial. Not easy to do but not impossible.
Another big obstacle in the path of ultimate happiness and peacefulness is the never ending desires. Its only when the living entity decides to desire, he gives birth to distress. So true "desiring" is the first step on the ladder that leads to "distress", now there is one more angle to this, if I do not desire than how shall I see progress, is it material progress I am talking about. To achieve any material progress is nothing wrong, but to desire it out of lust or greed completely changes the path. The main point is how we look at it, if i intend to desire something because it ought to be done for the benefit of myself and the mankind on the whole then it does not result in gain or loss, its only seen as a duty or as a will of God having no karmic reactions.
This entire material universe is full of miseries because what we understand as happiness is also of temporary nature. And anything like temporary happiness finally results in unhappiness when your happiness ends. Happiness is one that thing, we should not run after. Running after happiness, happiness runs away further. So drop it completely,drop the very thought to achieve it and just go with the flow. To go with the flow is in itself happiness. Start enjoying "within". Let the mind go blank, Let the spirit within know its real self. Let the eternal soul feel the super soul, let the Transcendental "Om" substitute the life air. Let the blissfulness take over the material happiness.Let God hold our hand and take us to his heavenly abode, the replica of which is the beautiful nature that we experience on this material planet.