The least important questions of all time.
Is there a god?
I have no reason to think so, and some reason to think not. But, it really doesn't seem to matter. With a god (or gods), or without: We are still affected by our decisions, and other's decisions still affect us. We still have to work to live. We still do better in groups than alone. We still have to work within the confines of our society and its mores. We still blunder into suffering - whether we "deserve" it or not. We still blunder into windfall - whether we "deserve" it or not.
Even if there is a powerful arbiter of justice out there punishing evil after life, the damage of that evil is still with us. We still have to clean up the mess ourselves. The suffering still happened. We still have to watch for evil to protect ourselves. We still have to work very hard to improve the conditions of our lives.
Is there an afterlife?
There is again no reason to think so, and more reason to think otherwise. But again, it doesn't seem to matter. What we do now, affects us now. Even if we're due an eternity of paradise, that doesn't excuse us from making the here and now a better place.
What we do leaves an impression on this world, even if it is just a small impression. If we die and simply cease to be, we still had an effect here. Even if we can't "see what comes next" or otherwise enjoy the long term fruits of our efforts, someone will. Isn't that a far greater motivator than the idea that we won't "really" die?
My instinct for self-preservation says it's an important question - but that's its job. It sees everything as a matter of "stay alive", and it is too stupid to deal with the fact that I can't stay alive forever. I can't let such a simple beast make my decisions about how to live.
In the end, I don't really give the slightest little shit whether others believe in god or an afterlife or not. I'm concerned with here and now. Which is why I dislike religion, as odd as that may sound. Religions tend to be a collective effort to ignore the here and now. They tend to put all one's eggs in a single basket that doesn't exist yet - and probably never will.
Think of what could have been done if all the effort put into prayer was put into answering the question "How can I make this better?" or better still "How can I make this better with and for others?" How much better might the world be if instead of a hundred "one true" paths we had a hundred "ways of helping".
Well, sadly, I don't really think we'd have any sort of utopia without religion's divisiveness, but I do feel safe in saying that more attention on here and now would do far more good than harm.