well I have tried OOP subclassing concept in Java class
but if you have oldschool,non-OOP thinking you probably have several PROC for each different but part similar function in game or other program
while OOP you start with a class,which have all the similar code and subclass it to different things
good example would be Finite State Machine,for RTS game,only few changes add the typical behaviour for the different kind of fighter
I want to reuse several GUI buttons,for different things,for example if finding a treasure box,it give me alternative todo with it,fighting gives me that kind of alternatives
or maybe a simplified solution with jumptable(s) ?,but that would become unreadable code compared to commented OOP code