Man possesses one or more of three primary qualities (guna): saatvika, raajsika and taamsika. All three qualities lead to different behavioral patterns in a man and bind him to this life.
Saatvika guna, is the purest and healthiest of them all. It doesn’t have any vices and enlightens one’s senses and conscience. A man in whom saatvika guna dominates, has his pain and vices destroyed and attains peace of mind. Laziness doesn’t exist in his world. He no longer has any interest in this world and he devotes himself to the worship of God. However, such a man can become proud of being happy or the knowledgeable one. It is this pride which hinders his unison with God.
Raajsika guna, is manifested in the form of affection for any thing living or non-living. It leads to desires and longing. It has the same relationship with these two as a seed has to a tree. The tree is born from a seed and it is the tree that creates the seed. Similarly, rajoguna leads to desires and it is desires which gives birth to rajoguna. Such a person believes he is the does of all his actions and that he deserves the fruits for them. It is this belief that binds him to this cycle of life and death.
Taamsika guna, as I understand it, is the most inferior of all the above qualities. It’s born from ignorance, where the senses and the conscience are weak and overpowered by emotional attachments. Tamoguna is predominant in a man who has pride and attachment to his body. It leads to ignorance and ignorance causes it. It exhibits in the form of sloth, indulgence and drowsiness in a man and through them binds him to this life.