Why am I an atheist and not agnostic or deist?

First off let me remind you that An atheist is a person WITHOUT a belief in any gods and not necessarily a person who believes "there is no god". No belief is required to belong to atheism, only the absence of a belief in gods is required. In this article I would just explain why am I an atheist rather than being a deist or an agnostic and I will not talk about the "ungodly" gods of those 2000 year old books.

The word "god" is so often used to describe something for which there is a lack of understanding in and which seems to be a very profound concept. "god" is a word which defines a deity. A deity is a supernatural being and has different powers depending on who you ask. In Monotheism, god is said to be a source of morality but not morality itself. In Polytheism, there is more than one god and the different gods rule over different aspects of life. In Deism,  the god is a supreme being who created the universe and he does not intervene in human affairs. In Agnosticism God is unknown...etc

Actualy the definition of god depends on the person you ask, previously I would define god as an infinite set of variables which most people will never understand, some others define him as our innate good nature, some define god as consciousness or the first cause...etc and there are more defined gods than humans.

Whoever you ask, agnostic or deist or anyone who is not an atheist, his god/belief is simply an emotionally/spiritual potent oversimplification of the unknown without any evidence.

Beyond a personal preference for a belief I think the word "god" is very problematic and very unnecessary. Beyond an historical sense it's neither needed nor helpful. For the sake of clear and precise communication the best solution by far is to ditch the word "god". Parsimony (Occam's razor) would negate an unknown entity for the purposes of reasoning humanistic values. If someone wants to believe in a deity/god/great spirit/etc. then they should be brought to understand that such a belief is at best incidental. As Laplace said of god to Napoleon regarding his work on celestial mechanics, I had no need of that hypothesis. Napoleon was a believer and Laplace could have appealed to a god but it was not necessary so he didn't. You won't find the word "god" as a psychological, sociological, or sociobiological scientific technical term in any textbook. And you won't for good reason. One more time, it's not needed other than for historical purposes.

For an atheist, the use of some words to refer to a god is useless, meaningless, irrational and unscientific. It refers in fact to nothing. The term God is applied so liberally that it really doesn't seem to hold any real meaning. It seems to be interchangeable with everything. So if one wants to say "love is my god" or "Justice is my god" or "X is my god". But then the term "god" becomes meaningless. It could literally be anything, therefore it is useless. It traded man's courage and relentless pursuit of answers for myth-based reasoning and a false sense of purpose and security. "God", for many people can be a good thing as it gives a focal point and something to look up to. But god can be very debilitating to man as well in his own greatness, as it prevents him from making progress in the areas where the dogma surrounding this god is dictated by this same god and it prohibits the productive analysis concerning critical areas of our lives like understanding our natural world (science) and understanding our "innate" good nature (morality).

To an atheist, Deists tend to personalize the meaning of the word god to the point of making it into nothing more than a box for which to place questions or doubts in an attempt to feel satisfied the questions and doubts are answered. To an atheist, it is meaningless when agnostics say that the existence  of gods is unknown without even defining what object called god and what object it refers to. 

For an atheist the word god is unnecessary as a response to the unknown simply because it is just a human idea which provide a necessary useless illusion.

For an atheist, anything that makes you see justice/love..etc as a spiritual thing and not as billions of connections in the brain which pick up sensory information and store and manipulate that information is useless and irrational. Just because something seems to be mystical or powerful or profound does not automatically deem it "godly".

To summarize, An atheist is a person who acts in a manner that takes into consideration actual "Critical Thought" and "Rational Thinking" and not proliferating the useless ideas caused by the lack of Critical Thinking in the first place. As an atheist I'm just keeping my thoughts simple without tending toward irrational. To me Atheism is obivously the only rational reasoning and the only philosophic doctrine that could lead to a timeless wisdom...