Why am I an atheist?

Theists and religious believers have never defined what god is.

What is god? How did he originate? Where does he live? What has he to do with man even if he exists? He does not seem to interact with the world in any way. If god interacts with our universe, the effects of his interaction must have some physical manifestation. Or, his interaction with our universe must be, in principle detectable. There is no physical manifestation or anything detectable. If god is essentially non detectable, it must be that he does not interact with our universe in any way. If god does not interact with our universe at all, it is of no importance whether he exists or not. A thing which cannot even be detected in principle does not logically exist.

Different religions have very different ideas of what god is like; they even disagree about basic issues such as how many gods there are, whether they're male or female, whether they have children or not. 

Every religion is different too; their similarity is superficial. It's worth mentioning that religions such as Buddhism and Taoism lack any sort of a concept of god. In the correct sense of the term they are atheistic religions. Christianity has a trinity of Gods. Judaism and Islam have one supreme God. Hinduism is pantheistic; there are thousands of gods. Some others are animistic.  In short, there is no consensus among religions as to what god actually is.

Even the ultimate purpose of life is different in each religion. Buddhism speaks of Nirvana-the cessation from attachment. For Christianity it is spiritual life with god in heaven. Islam’s heaven is a material one full of worldly pleasures. Hinduism promises Moksha- escape from life and rebirth cycles. There is no consensus here too. Even morality is altogether different. What is good in one religion can be bad or no good in another. What is strictly enforced in a faith has no meaning in another. In short their gods are different, their purpose of life is different and their morality is different.

Major religions have a number of conflicting sects too. Look at Christianity: there are many competing groups with different beliefs. Catholics, Protestants, Calvinists, Anglicans, Presbyterians, Orthodox-each one having a number of sub sects with their own theology and liturgy and each one convinced that it is true. Islam has Shiites, Sufis,and Sunnis and their denominations.

Religions have waged thousands of wars and their different sects have fought and killed each other. How are we supposed to decide which religion or sect is the true one? 

Theists should question their beliefs because of the very real harm they can cause to everyone. Religion represents a huge financial and work burden on mankind. It's not just a matter of religious believers wasting their money on churches/temples/mosques/pagodas and so on.  Think of all the time and effort spent building them, for praying, attending religious liturgy, sermons and classes. How all that effort could be better spent! This is a wrong focus of the resources of man. If the wealth and effort so earmarked is spent for poverty alleviation or for helping the orphaned, the crippled, the retarded and the imbeciles, this world would have been a better place  to live in.

Many religious people believe in miracle healing and they refuse to take the medicines prescribed to them by doctors, and dying as a result. Some of them refuse blood transfusions on religious grounds and die.Religions divide people and instill hatred and mistrust among them. Even people kill others in the name of their god probably to establish his superiority. Religion and gods have done more harm than god to man.
    

Atheists live their lives as though there is nobody watching over them. But their lives are not pointless. Many of the atheists live a purposeful life. They decide what they think gives meaning to their lives, and they pursue those goals. They try to make their lives count, not by wishing for eternal life, but by having an influence on other people who will live on. For example, an atheist may dedicate his life to a political or social reform movement, in the hope of leaving his mark on history.There are others who live loving and helping his fellow travelers or devote themselves to the service of mankind.

How do they find comfort in times of danger? That may sound like rather an empty and vulnerable way to face danger, but so what? Should individuals believe in things because they are comforting, or dodge reality as it is harsh?  Or should man believe in something because it is widespread? The thinking that a majority of the world population believes in some sort of a religion does not make it true or meaningful.

There are many scientists who are religious too. Recent surveys typically find that around 40% of scientists believe in God. (The most recent survey was done by Edward J. Larson and Larry Witham in 1996, and was reported in the journal "Nature.")  Many respected scientists have made themselves look foolish by speaking on subjects which lie outside their fields of expertise. The believing scientists are a minority anyway. Childhood indoctrination and programming their fertile minds from day one could be the real reason why people continue to believe in religions. Religious beliefs are passed on from parents to their progeny. If this indoctrination is stopped for one generation the death of religions is almost certain.

Please search for what is true, even if it makes you uncomfortable. It is no good to believe in an external power you do not know or understand. Just because something's popular doesn't mean it's good. Many of us believe things just because we want them to be true.  If you want to find some meaning for your life, it is up to you to find it.  It is worth trying to make the most of your life as it's probably the only one you'll ever have.