1. God

Let’s gets the easy one out of the way first. Sartre (Being & Nothingness) summed up the deal on the big fella: God is irrelevant, or to be more accurate, whether God exists or not is irrelevant. The argument is simple: the only thing nobody disputes about God is that if he exists, he didn't compel everybody to believe in him (something of an oversight, if you think about it). It follows from this that it remains up to each individual to find meaning and purpose in their own lives. Whether a being or a nothing, either way, God doesn’t help.