Once upon a time, 5 monkeys were kept in a cage.
The owner of the monkeys went to the cage and put in a ladder, and at the top of the ladder he hung a banana from some string.
As soon as he got out of the cage, one of the monkeys started climbing up the ladder to grab the banana. Slowly and cautiously he climbed higher and higher, until he reached the top and stretched out his hand to grab the banana.
Suddenly, the owner opened the cage and sprayed the other monkeys with water. They all ran to the corner and bunched together screaming and desperately trying to avoid the water. The other monkey looked on stunned, whilst he peeled the banana and started to eat it.
Later, the owner came back and put another ladder in, and strung up another banana. One of the monkeys got curious and started to climb the ladder. But, now terrified of getting soaked, the other monkeys ran and pulled him down before he could get to the top and started screaming at him. The monkeys had learnt that when one monkey climbs the ladder, the other monkeys get sprayed with water.
The owner returned and replaced one of the monkeys with a new monkey. Now there were 4 old monkeys and 1 new monkey. The owner once again put in the ladder, strung up another banana and waited. The new monkey, curious started reaching towards the ladder, but before he could even touch it the old monkeys pulled him down and screamed at him. The new monkey looked on confused.
The owner returned and replaced another of the old monkeys with another new monkey. Now there were 3 old monkeys and 2 new monkeys. Again, the ladder was put inside and the banana strung up at the top. The newest monkey looked at the banana with desire in his eyes. He started walking towards the ladder. The 3 older monkeys screamed at him and pulled him back, and the other new monkey was reluctant for a second, but then figured everyone was doing the same thing and so joined in with the screaming and pulling.
Eventually, the owner had replaced all of the old monkeys with new monkeys. He then put in another ladder, and banana. Whenever one of the monkeys went to climb the ladder, all the other monkeys would start pulling him back and screaming at him. They were so enthusiastic about doing this, but not a single monkey knew why they were doing this!
In this example, the historical context which formed the established routine is no longer relevant, but the routine is continued because all of those involved think “that’s just what is done around here”. At the end of the story, none of the 5 monkeys had ever been sprayed with water, but they continued the pulling and screaming and forbidding other monkeys from climbing the ladder because that’s what every monkey does.