Why do people believe in their religions?

I am not trying to offend any religion. But seriously, you grow up you realize theirs no Santa, no Easter bunny, and no God. After taking a year course on History of the Roman Catholic Church, I never saw any good come from the religion. Only controlling, war, persecutions, and for what? Just because your share the same religion, but see it in a different way. St. Peter: "Ok guys convert to this religion and wear this hat, and drink this food and cut this thingy off your wing wang, you might be executed, BUT YOU'LL THANK ME IN HEAVEN!" Look around people, war, disease, poverty, starvation, droughts. Why not throw it all away now?