You are right, people are focusing more on the physical aspects of a captain;

a) Has verbal diarrhea and can often be seen screaming at the top of his voice as though he was at a rock concert.
b) Acts like a 'tai kor' during confrontations with other players, pointing his finger in their face, asking him how he wants to 'settle'.
c) Goes into every challenge like the opposition player slept with his mother and told the whole world how bad she is in bed, like that nutter, Vinnie Jones (how does one get sent off after only 7 seconds?).

I won't deny the importance of these traits but I believe their mental attributes are more important;

a) Calm - Won't pop a vain when the ref gives a decision against him, proceeding to shower the ref in spit by protesting to him while an inch from his ear, and eventually getting himself sent off. Instead of taking out his mobile phone to call for backup, captains should do all they can to pacify their players so as to not get sent off by giving them and ice cream cone or a lollipop.

b) Intelligence - Can at least spell basic words and thus identify his teammates by the names on the back of their jerseys.

c) Spirit - I'm not suggesting that captains should become alcoholics like Tony Adams. I've always admired army generals that lead the charge, though I have serious doubts over them living a long life. Maybe I've been watching too many movies, but there is nothing more motivating than seeing your leader leading you into battle rather than staying at the back, playing with his PSP while you charge into battle.

d) Determination - Even when playing against a team of 300 Spartans, captains should inspire and motivate their teams to play above themselves. To dig deep when times are bleak and prove that even thought Arcadians grow flowers, sew baju or dance ballet for a living, they can kickass when required.