An extension of themselves, elevated to some imaginary supreme status. What better way for someone who can't see the sheer amazingness of existence to find validation for the otherwise empty listless shell of life they barely live?
Plus it's part of the group mentality, again, another bid for validation, importance, meaning.
Things are as they are, if there was some sort of divinity, that does not alter anything, just adds another layer, bit a layer that is superfluous because to anything divine we are just part of a swirl of microbes. By their very nature Gods would not need our approval to continue as they are, our prayers and rituals are insignificant as far as they would go.