If there is no life after death, what is the purpose of our lives on earth and how do you convince yourself that whatever you’re doing has meaning ?
Consider that we are infinitesimally small compared to the size of the universe, and our life spans are negligeble against the life span of the universe. And how human race never existed before “recently” and potentially cease to exist in the future (an assumption).
Our life on earth should be about making the world a better place, even if it's just by 0.00001%. Whatever you do would definitely has their meaning, see butterfly effect. For dramatization, see how 'alive' Einstein still is today.
I believe there is a God, but not one who care about how you wash your ass or if you pray to him. After all, if he needs our prayers that much, we should be the God to him. If he is kind enough to really grant us lives, he can't care enough whether or not you believe in him. If he cares that much, I don't really think he is as kind as glorified. Hence, I'm a deist.