Why Akagi Takenori has the worst personality, and why Yoo Chang-su is a true gentleman

Akagi: Reckless selfishness, hitting juniors, hitting classmates
Yoo Chang-su: The strongest in the series, but doesn't show off his strength unnecessarily
In fact, even after getting headbutted by Hanamichi Sakuragi and intentionally raising his shoulder to take the hit head-on,
his physical toughness is practically monstrous.
A true gentleman who even lets himself be run over by Rukawa's bicycle
On top of that, he shows a human side by knowing how to bow down and apologize when he is at fault.