The brain can fail and become diseased in multiple ways. Depending on which system gets compromised, the effects can be mild, or serious. The disorders of volition are well-known by those who study neuroscience, and those who suffer them. They are not a "trivial of inconvenience" and no amount of discipline can overcome them. What did I expect? From you nothing at all, because you are not well-versed in the topic, and you don't seem interested in learning about it.