He was entertaining, and he was mad, but there was also method to his madness. People debate about how much power he actually gained, and if he should be given any credit, but I think that he should and so far I haven't seen a single FF villain achieve half of the destruction which Kefka caused.
The guy was utterly loony and dangerous. He killed all these people without hesitation and wrecked the world before becoming a God-like entity towards the end. Plus there's an air of tragedy in Kefka's past that led to this as well.
For almost the exact same reasons why I like Zidane the best for male lead, Kuja gives you everything you want to see and hate about a main baddy. He goes as far as destroying his own home world when he is unleashed into Trance Kuja. Sure Kefka and Ex-Death did the same thing in their respective games, but Kuja's backstory or his ambition and power, to go as far as to rid his own brother so he could be on top shows how crazy, but powerful he really was.
Honestly this joker was in your face 24/7 all he wants to do is destroy the world.......he will definatly get you mad! .......he is the reason you actually play this game even after you beat him he will still remain in your head. (especially his laugh)