You're looking at it like we think that Christianity is nothing more than our ticket to a free lunch. Nothing could be further from the truth. We don't worship, and follow the commandments, and love our neighbor, and evangelize just so we can reap a reward. That's equating Christianity to using a Discover card just for the purchase rewards.
Christianity just is not that base. If our impetus for doing something is "what's in it for me," then that is antithetical to the very nature of Christianity, which is selfless love. We engage in our religion because we love God. We come together to say, "Thank you for being our God. What can we do to return your goodness?" We talk to people about Jesus, not because we "want them to go to heaven," but for the basic reason that Jesus is our savior. Jesus sets us free from the tyranny of self.
Christianity is really more about creating a lifestyle and a society in which selfless love is celebrated, in which the lifting of both the individual and humanity at large is celebrated, and in which we are freed from the very sort of petty, picayune legalism that you seem to want to thrust upon the religion.