Let me show you an interesting story about "five monkeys."
Five monkeys are caged by an experimenter. Inside the cage, hang a banana on a string and place a set of a ladder under it. Soon, a monkey starts to climb the ladder to reach the banana. But, as soon as he touches the ladder, all of the other monkeys are sprayed with cold water by the experimenter. For a while, another one tries to reach for the banana, and all the other monkeys are sprayed with cold water. Pretty soon, the monkeys try to stop any of their peers trying to reach the banana.
Then, the cold water punishment is stopped. And one monkey is removed from the cage and new one comes in. The new monkey sees the banana and tries to climb the ladder. Then all the other monkeys attack him to stop his act. After another attempt and attack, he knows that if he tries to climb the ladder he will be attacked.
Next, another of the original monkeys is removed and replaced. The newcomer tries to go to the ladder and is attacked. Interestingly, the previous newcomer joins in the punishment with enthusiasm. Then, the third monkey is replaced. And fourth and fifth original monkeys are replaced in sequence.
Every time the newest monkey tries to reach the banana he is attacked, even though most of the monkeys which beat him have no idea why they are doing this. After replacing all the original monkeys, none of the remaining monkeys have ever been sprayed with cold water. Nevertheless, no monkey approaches the ladder to reach for the banana.
Why? Because as far as they are concerned, that's the way it's always been done around there. This story may apply to group behavior of human beings. For instance, a company policy or a group norm can have disastrous consequences without critical insight.