Whose fault is it

The girl bought a pair of pants, which was too long after a try. She asked Grandma to help cut it short, but grandma said she was busy; she didn't have time to look for her mother; she didn't even have time to look for her sister. The girl fell asleep disappointedly. Grandma thought of her granddaughter's pants after finishing the housework, so she cut them a little short; sister cut them short again when she came back; mother also cut them short when she came back, and finally the pants couldn't be worn. -- The disadvantage of management lies in: either no matter what it is, or all of them are in charge!