It has been said that many self-described atheists are angry with God and as a result deny His presence. This is seen as stemming either from a belief that life is unfair in a general sense or that their life, in particular, has been unjust. This leads to an anger being directed at that being seen to be behind this life, namely, God.
Others atheists are seen to be angry at orthodox religion and because they associate a belief in God with these religions they think they have to deny God to vote "no" to these religions.
A third category are those who believe scientific discoveries have done away with the need to believe that a being or beings created the world we perceive. Instead they believe that an unguided (by intelligence) process created the universe from nothing and eventually led to the complex, highly organized world we see around us. Although this group does not believe in a creator God they do believe in the numerous miracles that were needed to create intelligent life forms out of inert matter and inert matter out of "nothing"!