At the ROCH Heroes Meeting, GJ almost killed YG; he had YG immobilized, and his hand was about to strike YG's head.
But then, YG's pink lips and intense eyes reminded GJ of YK's, and seeing how he never got over YK, that made him stop.
We can see what saved YG was his physical resemblance to his father. So, if YG didn't look like YK, would GJ have continued with the strike?