Bliss
Bliss is a superlative state which is far above and beyond happiness. The happiness that we commonly refer to is in some way or the other related to the external world. But Bliss on the other hand is an experience pertaining to the soul and is not related to external stimulii.
In life we find that whatever makes us happy has the potential to make us unhappy. To understand this further, we have to study the mediums through which we experience happiness.
They are:
The five senses: These are pleasures gained through the experience of touch, taste, sound, smell or sight.
The mind: It is that part of one's thoughts that are linked with one's emotions (our emotions and thoughts are interwoven with each other – unhappy thoughts lead to unhappy feelings and vice-versa). Pleasure gained through the mind is far superior to that gained through the five senses.
The intellect: This is our decision making and reasoning ability. It allows us to experience a different kind of pleasure that is qualitatively and quantitatively superior to the happiness gained through the mind.