MOSS: He made up those rules, and we're working for him. (1.2.170-171)
The rules of the game are in place to keep people like Moss down. He's busting his butt out there every day, but he can't do what he wants because someone else is calling the shots.
MOSS: That's right. It's a crime. It is a crime. It's also very safe. (1.2.267-268)
Who cares about the rules if you don't get caught, right? This gives good insight into Moss's character—this is not a guy who sees right and wrong as black and white. Sure, it's a crime, but that's not the important thing. The important thing is it can be pulled off, it can benefit him, and he can get away with it.
ROMA: You've got a fuckin', you've… a… who is this...? (2.1.43-44)
You know a good way to show total disrespect for someone? Refuse to even acknowledge their position in society. Roma knows the guy is a cop, and he knows what that means, but he will not admit that this guy has any power over him. "Who is this?" he asks, like the cop is a nobody.