Why do I believe Santa is real? Faith!
It seems that in order for religion to really stick (last a lifetime) it must be introduced as a child. A child’s untried mind, peopled with fanciful characters as real as any (Santa Claus, Tooth Fairy, etc.) represents just the level of thought processes necessary for acceptance of a religious system so rooted in superstition and mythology. An adult tells the child of Santa Claus and the child believes, whole heartedly that he exists. If that child was protected and isolated from those that would tell him otherwise and surrounded by those that would continue to encourage his belief in Santa, would said child ever stop believing in Santa? How is this different than belief in God (Jesus)?