Bad story idea: AGI is successfully developed with a complex reward system surrounding a sort of points counter; almost immediately figures out how to directly manipulate the value & converts all resources into computronium to store the largest possible number. Wireheads forever.
Highly addictive drugs sort of hack the system that reinforces behavior (“do more of whatever preceded this feeling”). The relationship between that & pleasure & meaning is messy, but you don’t need meaning to have self-reinforcing behaviors.