If we could realize the significance of human birth, it would not even take a day to attain God. The human body is so important that even Indra, the king of heaven, who is worshiped by human beings, desires to be born as a human himself. The human body is a very complex machine and there is no other body as complex as that of a human. We strive to maintain a very healthy body, yet suffer from many an ailment due to improper habits and the prevailing environment. In addition, an average human suffers innumerable miseries as a result of illness and death of loved ones. It is amazing how we humans are able to continue living. However, there is a wonderful power that we humans possess - knowledge.
Granted that we attained human birth due to our own actions, but it was God who took note of our actions, and rewarded us by making us human. God did all this for us. Actions cannot yield results on their own. Let us say you donated $100,000. This act of charity will not yield fruit by itself. God will have to intervene and give you the fruits of your donation. So, God is merciful in that he rewards us for our actions. Otherwise, we would never have attained human birth.
God has gifted us a human body due to his compassionate nature. Reflect upon this repeatedly; reflect upon this fact thousands of times. We are suffering because we fail to contemplate properly. What are we thinking? "How should I spend my time?" We are constantly planning on how to earn more wealth, constructing a house and leaving behind a large fortune for wife and kids. There seems to be no concern about our own spiritual upliftment. We must think about why we have come to this world. Our lives are wasted in planning how to make the body happy, and we work towards those plans. Still, we fail because our desires keep tormenting us. We may sleep on a bed of gold studded with diamonds, but we still suffer from inside. Happiness comes from within, not from external objects.