If you are feeling very happy, you don't have to speak about it. 
Happiness is its own thing and needs no words; 
It doesn't even need to be thought about. 
But the instant you start to say, 'I am happy,' this innocence is lost. 
You have created a gap, however small, 
Between yourself and the genuine feeling.  ~ Jiddu Krishnamurti

There, he reveals the innocence of true bliss, which truly belongs to the individual and does not depend upon any 'outside' factor.

Let us proceed in the scientific way. Imagine that you are conducting an experiment in a science lab. You put together the apparatus, the chemicals and proceed to combine them and observe the reactions closely. This is what happens within an individual, regardless of the fact, whether anyone is consciously observing or not. Day in and day out, the varied reactions explicit and implicit, observed and unobserved ceaselessly occur, the stimulus is varied, sometimes, it is from within, sometimes outside. And often it is not 'real' at all.

Everything occurs on the plane of the mind and within the mind substance. Only when the strongest of forces come together this mind play is reflected into reality. Noted thinkers, philosophers and analysts of the past, right from Plato to Bertrand Russell, Karl Jung and Freud have time and again elicited that what seems 'real' to us is in fact 'unreal.' Everything occurs first in the 'mind' therefore at least hypothetically we can say that mind is the substance which offers 'space' for creation. Remember again that 'it' (mind) is not the 'creator.' Who then is the creator? Ancient Indian scriptures, the Gita, Upanishads and Vedas all of these go into varied depths to analyze and point out the 'creator' within the human domain.

Creativity is filled in the 'life force' that keeps us alive and therefore it permeates all, even the smallest cell in the human body is full of 'creative power.' So also, in all other living beings. The flower bud possesses the knowledge to bloom and when its cells use this knowledge, irrespective of external factors, like weather, dust, pollution, the flower will bloom and defeat the negating factors, or those factors that retard its blooming. This is a natural process. It is complete and full-proof in all living beings. And the right use of this knowledge brings happiness to all ' the flower, onlooker and the imposing external factors, as well. Thus, even in smallest of God's creation we see that His might overrides all negating factors. This knowledge fills you with a feeling of blessedness ' bliss. Even simply reading the aforementioned sentences with involvement and feeling will make you feel truly blissful.

Has anything happened to you from the moment you took, up to browse through these lines on 'Happiness,' intellectually speaking, nothing. But if you look within, you are experiencing a mystical tranquility and divine happiness. It is in such prolonged moments of tranquility and happiness that man's divine nature manifests itself. This nature knows no bounds, it is pure and indomitable. It is pure power, sheer light and nothing more and less.

Happiness therefore is a natural state. Peaceful minds are always happy. Happy minds need to be made 'grateful' by the power of prayer and right meditation. This will ensure that the individual goes on living happily ever after'

Happiness and sorrow both are states of the mind, once you know the art and technique of making your mind immune to all of these factors and keep it supremely concentrated on the divine force within, you will always experience a state of happiness, irrespective of external conditions. This is the 'ideal' state. In reality however, such a high degree of idealism is not expected. Man has to play his roles that of son, husband, father, brother, mother, daughter and wife well and yet remain immune from within to the 'roller-coaster ride' of fate. Here we come to yet another, power which unleashes within the human consciousness with continual practice of deep contemplation and meditation ' a power awakens within each one, which is able to attune itself and harmoniously to the will of the Supreme or Laws of the Universe. And then growth of the individual both material and spiritual occurs in harmony with the laws of the Universe and this opens up doors of eternal peace and happiness for that individual. It is then that man learns to master his destiny and reign the kingdom of his mind so as to sail smoothly on the sea of life.

Happiness therefore is truly eternal and is commensurate to good physical and mental health. An individual who is truly at peace and is happy in the aforementioned state can only 'progress' through life, transcending steadily to higher realms of consciousness spreading good cheer and harmony through his life and work.

'All common things, each day's events,
That with the hour begin and end;
Our pleasures and our discontents
Are rounds by which we may ascend' ~ James Allen