
There are still many polytheistic (many-gods) religions being practiced in the world today, the most familiar being the Hindu faith, which lists more than 1000 separate deities in their pantheon of gods.
So, how does that work?
If you ask a Hindu which god he or she worships, he or she will tell you that they prefer one manifestation of god over another, but that the manifestations all represent one "sense of deity" that is reflected in thousands of ways. Ganesha, who is represented as a seated man with the head of an elephant, is one; Krishna is another. Krishna, in turn, is said to be the 8th manifestation of Vishnu the creator; in that respect, Krishna is a reincarnated god from another god.
It can get very confusing, but the principle is the same: each god represents an aspect of belief that is slightly different from the others, so that each believer can experience god in the way that best suits them at a particular time. Many family members in one family can all be worshipping different gods, because each one worships the god that most resembles what they need and expect from their god at the time.
Imagine having a god that is whatever you wish it to be, with faces and aspects that change depending on what you can understand and appreciate.
Now imagine your God.
See the difference?