For me it helps to add a little bit of his morals.
Where does his behavior come from?
Pride can come from having family or people that kept looking down on them so they feel the urge to priof themselves.
It can also be a self-assigned prophecy where he was put down as a badboy so he started acting like it ‘if no one sees me as anything but, then why try to be anything else’.
It can also be a defence mechanism to act tough but on the inside they are softer.
After that you can start finding reasons why and when you have simular situations or to spice things up, a new situation that goes against what they are used to:
Exp:
Someone talking back to them
Someone more powerful
Someone who cares
Etc.