Why does it matter, as long as you are a good person?

All I see is an argument on if God is real or not. People insulting each other and saying "you will burn in the lake of fire" and sh*t like that. I say why argue? If you live a life of caring and helping people around you and are generally a good person, why does it matter if they believe or not? If I don't except Jesus as my savior or believe in any God or if I'm the most devout Christian/Muslim/Hindu, as long as we live a life of peace instead of arguing and fighting, why does it matter. I've been told if I don't accept Jesus then I will be sent to Hell upon my death. So if I did nothing seriously wrong in my life and died saving numerous orphan children from a burning building but never accepted Jesus, I'm going to Hell?