Well, there was one time he cried. In the hospital when Grissom came to see him in "Fannysmackin'." He was upset in general, upset he hurt that guy, and upset about his parents. It's also one of the few times Greg opened up about his parents, truthfully. I really wish they would give us a Nick/Greg bonding moment (No, not that. I told you guys that you have filthy minds!), but something where one opens up to the other about (Why is everything sounding sexual??). You know, instead of Greg trying to impress Nick all the time.