Obsessive-compulsive Disorder

I have seen a movie which the leading man has obsessive-compulsive disorder before. He can't stand any condition without following his willing. He must go to the same restaurant, and order the same meal with the same waitress. Before going to bed, he needs to check whether or not the door is locked for three times. Something like that. I was very impressed by his behavior. I hope that I wouldn't be like him.