Disease: Ujub (exalting the blessing and forgetting who gave you the blessing)
Imam Al Ghazali said the difference between ujub and kibr is that kibr needs two people:
The Mutakkabir (arrogant one) and the Mutakkabir alayhi (he one whom arrogance is shown).
A Mu’ajjib doesn’t need a second person, he is one that is simply impressed with himself. The definition of uju is exalting the blessing and forgetting who gave you the blessing. In this culture when someone says “You are beautiful”, we say “Thank you” as if we had anything to do with it. If Allah subhanahu wa t’ala made someone beautiful/talented/ etc then they should praise Allah subhanahu wa t’ala. “The Master of Rhetoric is he who speaks so eloquently, that people think I can do that too.” “I worked so hard and I made it!” People think that its by their accomplishment that they were successful instead of Allah’s aid. “Allah subhanahu wa t’ala makes every creator and his creation”, so airplanes, cars, computers, etc are all creations of Allah. Once you realise that you will lose your ujub over anyone who knows something there is someone who knows more, this is characterised in the story of Musa and Al Khidhr.
Vanity is excessive pride in ones accomplishment or beauty. The root meaning of vanity is emptiness. There’s always another side to things. As a result of your impotence you can neither create any benefit nor harm. Ignorance of Allah’s Will and Mastery over creation leads to foolishness like ujub.