When people tell me they believe in god, it usaully means one of three things: 1. The believer does not understand evolution 2. The believer understands evolution and willfully disregards the evidence 3. The believer understands evolution but hasn't had the light bulb turn on
Now just because evolution is a thing doesn't mean that god can't exist. Arguments can range from god is the first cause of the big bang or god inseminated the earth with self-replicating DNA. But if you really sit there and think about evolution, specifically primates, shit starts to make sense really quickly.
Although chimpanzees are our cousins and a distinct lineage, let's imagine chimpanzees are our ancestors. They exhibit a little bit of self-awareness, use rudimentary technology, have social structures etc. Through the course of evolution over hundreds of thousands of years, the chimp starts to get better at what he does.
He starts standing up a little straighter. He gets a little taller and faster. He takes that stick he used to prod termite mounds with and sharpens it so he can stab prey running away. He refines his grunts and groans into a few words to communicate at a distance. He figures out patterns in the stars and moon that direct him to where his prey will be. He realizes that the sun makes his seeds grow because seeds in the shade don't. He starts to contemplate what all those things in the sky are and gives them names and personalities (religions of sumer, babylonia, etc). Well eventually all things that he can't understand like lightning, love, and epilepsy have names and personalities (greek and roman religions). Eventually there are so many names it all gets confusing because others keep making up stories about why stuff happens in nature. But then another group comes along and says "Hey we have just one big guy its really easy just follow these rules and read this book and everything will be cool." Obviously that is the abrahamic religions. If you are a christian pastor, you're teaching a simplified version of ancient mythology.
Primates are all very heirarchal so we long for a father figure to take care of us and protect us. God fills that niche. We humans look up at the stars and wonder what could be up there. We look at the other forms of life on earth and wonder why are we so different. Most times, an individual comes to the conclusion that we as a species are entirely insignificant and our death is no more special than the death of the chicken you ate for dinner last night. That scares the shit out of most people who think about it negatively. So we create stories and myths in an attempt to convince ourselves that we are special. It is man's realization of his insignificance and the absurdity of life that scares him into believing.
Rather than let it scare you, think about it a little differently. The story of your life is made by YOU, not some god that decided it a long time ago. If you are looking for a purpose to life, then realize your only purpose is to reproduce and propagate your DNA. If you're looking for meaning to life, get the fuck out there and create it for yourself. Don't be lazy and just accept what another group tells you. And as you live your life always keep in your mind how absurd life is, the statistical improbability of being alive in this universe, and how lucky you are to experience it.