Answer:
There were large difference between two upper estates (clergy and nobility) and the third estate (bourgeoise). Third estate had to pay all the taxes, practically had not political authority and could not participate in the process of decision making. Therefore, it was just a matter of time when the third estate will defy the established system.
Explanation:
This large differences at the end led to Revolution. King and two estates didn't understand the needs of third estate. They imposed larger taxes, didn't allow them to speak out and at the end they started rebelling. Old, feudal hierarchy couldn't exist anymore.
