Do you ever think about why we ended up with so many religions and what separates them so much while having common things ? I do and I believe they not so different in origins as well.
We are curious creatures. We are never satisfied with what we perceive. Likewise, we explore and experiment with things we don't understand and analyze ourselves collectively to come of with theories about our behavior. Further, as creatures with enough intellect to understand the harmony of nature, Everything we do, our curiosity is what drives us.
The reason to explain
We are not perfect, and we suffer from our limited life and interconnected emotions, the more connected we are, the more these emotions take over us. And then, we are left with questions when a phenomenon occurs, which is beyond our intellect. So, we feel the need to explain these unexplored phenomena to most of us. We also feel the need of something to bind us together and make us follow some conducts to control ourselves. But since we are widespread across the globe, this results in various such efforts.
And that's how we have religions. Since most of us had the same questions, we often came up with similar answers, which resulted in similar teachings and beliefs. The difference between them is because they were invented in different time-spans and under different circumstances. With a little exploration around these religions, we can realize that while people took their own path to explore and answer, the similarity existed due to the nature of questions they were seeking answers for, and the difference was there due to different time-span and locality.
The special ones
Among these, there were some religions, with diverse and wide locality and a long time-span to evolve. This resulted in exploration of various fields, turning them into very diverse and complex religions. They tried exploring things that others didn't try.
They questioned their existence. While they came up with arts of mental and physical improvement, some of them reached beyond the limits of known. Their outlook towards human life changed, and they jotted down most of their studies.
And finally, they came of with a wide variety of stories to make life easier for those who were not as capable as them.
The time passed and people started getting corrupt with power and knowledge beyond their abilities, since those who were able to handle this knowledge and power peacefully were uninterested in this.
With this corruption, people ended up altering these teachings to their own comfort. With time, people lost the ability to reach that level of intellect, turning back on these teachings and started believing all the stories.
That's what I understand, analyzing these religions. They sure were created to answer questions and bind people at first, but with time, people turned them into the very problem they were trying to solve.