It is necessary to follow the MLA rules because academia needs standards for organization. There is no way a society could function without standards. Imagine if each house builder could place a door on a house with any size the builder wanted (instead of matching the door size to the house). There would be no locker, no nail; nothing would fit the door because the builders door would be either too large or too small. Imagine also if a car manufacturer could design a car of any size the manufacturer wanted (instead of tailoring car width to the width of the highway). If the car is bigger than the standard size, car drivers will not be able to drive on the road because the cars would not fit on the highway. Standards such as MLA Format Annotated Bibliography work in the same manner. They exist to give extra quality to academic work.