The History
In the Medieval period society was very codified. Meaning it was strictly, and systematically governed by laws. Such laws can be moral (biblical and enforced by the church), formal (enforced by the ruling power/police), or societal. By societal law, I am referring to laws which are dictated and enforced by societies and cultures. These laws are informal in nature, but this in no way lessens the serious affect they had on people.
This post will focus on two intersecting, and correlational laws. The first is the moral and ethical code referred to as chivalry. According to this code you must: obey those placed in authority, fear god and maintain 'his' church (respect/uphold religious authority), and always serve your liege lord. This basically called for an unconditional, and unquestioning faith in authority.
There were also laws that arranged society into different classes of people. Known as the feudal class hierarchy the few and powerful were at the top, and the many and powerless were at the bottom. The hierarchy was as follows: God and his earthy representative at the top, followed by the Monarch, nobles (liege lords), knights, the working class (merchants, and farmers) and then came peasants in at last place. There was no room to maneuver in the system. The class you were born into would most likely be the class you died in.
The Custom:
Therefore, it was customary to respect those in authority. The aforementioned laws inherently enforced and perpetuated this class hierarchy. Well, technically all Medieval laws did. By engineering obedient, unquestioning members of society the class hierarchy remained unchallenged. It would be anarchy to transcend the class (with all its barriers) that you were born into.
Most people are still taught to respect authority, and to do as they are told. For the most part there is no harm in this. Children should respect parents and teachers, adults should respect the law, etc. However, when you raise a population from birth to blindly do as they are told things can go from good, to bad, to worse very quickly.
The verdict: Leave it (stick it to the man)
I would like to clarify: I am not saying loose all respect for authority. Rather, do not blindly adhere to those who hold positions of power. Question, debate, and engage in your government, relationships, and lives. Do what you are told, only if it is the right thing to do. For example: it is a good thing to obey the speed limit, and other laws. But, it was also a good thing that Dr. Martin Luther King challenged power structures, and societal norms which were backward and unjust.