What, in your opinion, is bad and what is good about feudal relations between seniors and vassals?

I believe that on the one hand, such relations are good, because they are stable and understandable to both sides: the feudal lords protect their vassals, the vassals of the lords – a kind of patriarchal relationship in society. The lord also gives the peasants the minimum necessary for life.
But, on the other hand, it fetters society, because even if you are talented, you will not be able to change your social status. You cannot leave this system painlessly. If you try to live differently, you will be destroyed.