If you are unaware of Pascal’s Wager, it is quite famous in apologetic circles. Blaise Pascal was a seventeenth-century French mathematician, physicist, and philosopher who applied mathematics to faith in a Christian God (he had no other god options if he wanted to live). It went something like this: we are all betting our lives either that God does or does not exist. If God actually does exist and assuming the gain (eternal life in Heaven) or loss (eternal life in Hell) are real, rational people should live as though God exists and seek to believe in God. If God does not actually exist, such a person will have only a finite loss (some pleasures, a few luxuries, whatever). Note this was before probability theory in mathematics had been developed, hence the novelty of the argument then and its mundaneness now.
The flip side is this: if you live your life in expectation of a reward in the next, you are not living your own life, you are living a life at somebody else’s direction. And, if there is no reward, you would have wasted the one and only life you will have. This is not the loss of a few pleasures, or a few luxuries, this is the loss of the self.
If it turns out that there is a god and he has created a hell, then you might want to ask him why outside of a miniscule speck of land in the Middle East, not a single scholar, mystic, seer, shaman, professor, judge, priest, or wise man heard or wrote his name, yet they wrote of thousands of other beings? If he was the source of all justice, what justice is there in not telling untold millions of people what the real rules are? And why were so many of the people who supposedly “got the message” such venal and evil people (Inquisitors, Crusaders, Bishops, Cardinals, Popes, etc.)? How was one supposed to see that god amongst the filth and squalor that was the life of the vast majority in Christian lands? Why was it not enough to live a simple life doing as little harm and as much good as one could?