( There's red-hot anger threatening to boil over and spill from the pits of his stomach again. )

Don't do that.

( If even talking about the guy's taking this much of an emotional toll on Dave, he doesn't want to think about how bad it could get if Dave has to confront the guy face-to-face. )

It's between me and him now. There's no need for you to get involved.

( The way things are, he can just kick the guy's ass and make sure he stays away for good. If Dave involves himself and gets hurt, Bro doesn't think he'll be satisfied to end things with an ass-kicking. )

You said he was a douchebag, yeah? There's no reasoning with those.