Nothing wrong with Luiz's extrovert behavior but you would expect a captain of a club to be mature and not being so crazy like Luiz is. It's so much more than just leading a team on the pitch. You're basically representing the club as a whole on and off the pitch when you are the captain. Right now, I don't think Luiz is captain material yet. And with him being a constant joker in the dressing room, there's always a strong possibility that other players may not take him seriously when he's giving orders, barking out instructions on the pitch etc.