Why are people a lot like sheep?

People who are really religious are like sheep... They read the bible, and it's the law, it's the final word on everything. They don't question it. There are so many religions out there, some say you have to fast for x amount of days and others have you doing other crap. Do people never question their religion??? My dad has recently turned into a 'bible thumper' since his grandmother has ped. He's been breathing down my neck to do this that and the other thing when it comes to religion cause apparently he's in 'the right' and 'the only' religion... Now I'm guessing that he thinks it's the 'right religion' because it was the first... How does being the first really make it the right one? I don't think god ever said that x was the right and only religion... as far as I know MAN created religion and it's retarded rules. I'm not an atheist, but I think they have some really good points when it comes to religion.