Did he always look mad after that goal? Maybe so, but I sure can understand he wasn't happy with the situation. As you probably know, our (pretty great) season almost turned to shit after the Chelsea game.
He didn't want to be captain: That's a bit strange, but who knows the reason(s) behind this. After all it's only a friendly.
He looked pissed after scoring the goal: He scored a penalty, in a friendly game, against Vicenza, which we didn't even win. Obviously he doesn't care for the team!
Seriously, I would be more concerned had he actually celebrated.
There were a lot of players who weren't really smiling during the presentation.
I agree that Trez sometimes makes "weird" comments or "strange" gestures but that can also be interpreted in a different way: he cares for the team.
I have a feeling Trez will score a lot of goals next season. I just hope it's with us.