What reason does Gerry give when he tells Julius that he honestly thinks he is a waste of god given talent?

Gerry tells Julius that he believes he is wasting his talent because Julius has the potential to achieve greatness but is not fully applying himself or making the most of his abilities. He emphasizes that Julius is capable of so much more if he commits to his goals and works hard. Gerry's comment reflects his frustration at seeing someone with such potential not live up to it. Ultimately, he wants Julius to realize his worth and strive for success.