Attention: I'm basing my idea under the Religion "Christianity", also I also based this on my expirience and information, you could share some, and correct me, but please dont flame 
I'm just in for the Lifestyle and the temporary peace that it makes.
If you all can see, when people are in vain, down, financially broke, got in an accident, having an operation, anything that is very very depressing and/or sad. They seek God for help and protection. Asking forgiveness at his feet, pleading for their sins to be atoned and stuff. Ask Blessings and Good Luck, Traditions and other superstitions.
But if everything is in up-see-daisy moments, and all fun, anything related to FUN or extreme happiness. Barely handful of people remembered God. Trust me, even me.
I just think of it that heavy restrictions of the Christian Religion made the whole world a bit of a better place, just like rules on the road, to avoid having an accident follow the sings and obey traffic laws. Though some Biblical rules are absurd they were somehow the back bone rule of some % of people. Technology has changed the way we live and relay information spreading 10 folds the speed of a wildfire, new excavation an discovery has change our trust and our beliefs are to fade. We mostly judge what we see and experience, rather than belief and superstition. But strangely it seams, i heard millions of people changed their life on devotion to God. From 1 of the most WANTED people who as murdered over 5 families, beheading more than 4 people, ranked Sgt. in a rebel group, soon turned to a mere Pastor frail as a feather, he in one of our Respected Regional pastors here in Mindanao, Phil. <-sounds exaggerated but its true! And in the other side of the story some people who are once the very devoted to God, becomes one that the religion feared to become the most. I have a teacher in here who was once a devoted christian, he chose to be a Priest when he graduates High school, in an unknown reason he became a drunkard, heavy smoking jerk, and just kept saying the he dont believes in God. I have no problem with that, about never believing in God, my problem is him, hes fking annoying, his friends said that he was not like that before. i care less why.
The Concept of the rules of God, was backed up by the concept that he is there in the heavens and watching you and your every move, then the concept is backed up by another concept Heaven and Hell, Heaven is the reward to those people who follow his rule and repent for their sins. Hell is the place for punishment to the sins you have done and not repented. And their and Priest and Pastors that just on reminding you about this.
Information about the world and studies that have been successfully conducted, was scarce long long ago. Relaying information at that time was hard and sometimes dangerous. People that have made a scientific breakthrough and shown to the population has sometimes end up in the stakes where people are burned because the population thought that the breakthrough was witchcraft.
Just a thought: I think that Priest took advantage of the peoples ignorance that time because the people has no idea about the information that they really need to know the most. This may be heard as a Bad thing, as for me, i think its a good thing, people those days are very vicious and chaotic, taming them would be hard and maybe dangerous.
Also in the court the Bible is used right? "tell the truth and nothing but the truth" thing? it this still present up to date? >_>
I think the concept of God is not a bad idea, having the % of people following its laws has definitely reduced the % of crime rates in some country. Just imagine without that very hard and heavy restriction that God has made for us... how chaotic the world turned out to be now?
The whole thing just came out of my head... now i'm exhausted.

Do i believe in God? No. I do follow his laws though... so what kind of term people used to describe me?