When he's doing tasks that don't involve fighting, he excels at it.
The protagonists and antagonists all have very complex personalities, backstories, motivations, and goals that require hours of watching the show to fully uncover.
He refuses to accept himself as inferior to any opponent that he disagrees with, including those clearly stronger than him.
He does this to make money and could have beaten the contestants easily but held back.
Instead, focused on establishing Killua and Gon as rival examinees.
He essentially went through a complete mental breakdown, with two voices in his head alternatively or Unfortunately for Pitou, he eventually settles for the latter.
After his transformation, he loses his right arm to Pitou.
People quickly change their tune and call him once they get a glimpse of his superhuman abilities and aura, usually the time they are eating a Rock to their face.