I'm a Christian because the multifaceted identity and nature of the Christian God presented in Christian theology tie both into the natures I've observed in the world that have helped to advance individuals and humanity as a whole and into the nature underpinning the existence of the universe and the arguments for God's existence.
Additionally, what I have managed to glean from both the Bible and prayer honestly stagger me, I could look over the same story in Genesis for example and notice a bunch of profound shit in there, and then look at it again and have my mind blown by something else, leading me to believe it's a resource I doubt I'll ever truly hit the bottom of in my life. It's like an ongoing dialogue where I find wisdom from my life experiences reflected in Christianity and get expanded by it, and wisdom from Christianity reflected in my life experiences and expanded by that.
One of the most profound things is the elucidation of the greatest dilemma faced by humanity and the solution to it. Genesis sets the claim that with the emergence of self-consciousness we became aware of good and evil, vulnerability, suffering and tragedy, etc. and became ashamed of our own vulnerability and shortcomings and hid, refusing to live authentically and instead developed arrogance, arrogance pulling us into the sinful patterns of things like resentfulness, covetousness, and irresponsibility. Christ demonstrated the proper response to vulnerability and tragedy which was to honestly confront it and take voluntarily accept that burden, moving forward with love and humility, and in doing so we transform ourselves into more heroic individuals willing to atone for our mistakes, forgive others for theirs, sacrifice on behalf of what is good, and adopt proper responsibility in our lives. By doing this we attain meaning in our lives to set against the challenges of the world and become more equipped to help ourselves and other people against them. In this respect I not only believe Christ to be the cosmic savior for the eternal afterlife, but for this life as well as he presents the proper path to confronting our vulnerability and limitations as well as the suffering of the world.
In my practice of Christianity I have found myself continually granted new insight, and transformed into a better person. I'm not perfect, I still find myself possessed by arrogance at times, feeling resentment towards people I come into conflict with, and being irresponsible towards things I know I should be dealing with, but my beliefs motivate me to try and be less and less like that with each passing day, and I have a lot more genuine appreciation for myself and for other people as a consequence of that pursuit and feel much more at peace with myself.
In respect to everything I just said, if I die and it turns out there is no God and no afterlife, I have no regrets about the pursuit I've given myself over to in life.
As for what it would take for me to stop believing, one of two things. The first is evidence that I'm wrong, since the reasons that have earned my faith are more compelling than skeptical doubt. The second would be a complete moral collapse of my character, which I would likely rationalize by abandoning my faith to justify doing whatever I wanted.
Spoiler:
What it won't be that makes me stop believing is snark on an internet forum from someone with a hateboner for religion.