The main problem with religion is everyone thinks their god is THE god. 
But how can you blame them? They're taught to believe in their God and told what to believe ever since they were a child. It's very hard to change someone's views when they've been told the same thing their whole life.
Sure, it may be true for some, but it is not true for all people;
some people come to believe in ONE God through their own efforts at self-education.
I am an example of one who formerly did not believe, but sought the truth and did find it;
it is not all that unusual, my friend; not everyone who believes is brainwashed from birth.
There are even famous atheists who change their way of thinking; one example is:
Antony Flew, a champion of atheist beliefs for more than 50 years. In a news article titled "Atheist Discovers 'The Science of God'": "One of Britain's most prominent atheists has decided that God might exist after all. Professor Antony Flew now believes there is scientific evidence supporting the theory of some sort of intelligence behind the creation the universe. Professor Flew, 81, a professor emeritus of philosophy at the University of Reading, said that this was the only explanation for the origin of life ... "I'm thinking of a God very different from the God of the Christian and far and away from the God of Islam, because both are depicted as omnipotent Oriental despots - cosmic Saddam Husseins," he said in his new video, "Has Science Discovered God?"
The problem with religion is that it attempts to separate the human from God;
God resides within you, everyone is capable of following the golden rule, it is ingrained into human consciousness.
All monotheists acknowledge only ONE God, so they are really all talking about the same intelligence as described by Anthony Flew above.