A not-so-rare incurable disease of which you can either be born with or it can be passed on to you through significant exposure to a person(s) infected with Full Blown Jackass, In cases of the latter it would be referred to as Second-Hand Jackass.

Referred to by Physicians as FBJ

Symptoms of FBJ are as follows:

Uncontrollable Hatred of everything and everyone,
Unreasoned Dislike,
Arbitrary Asinineness,
Inability to speak Truth,
Extreme Cynicism,
Unnecessary Sarcasm,
Irrational Aggravation,
and Inconsideration