The Captain Class - by Kent Beck [emphasis added]
These captains, in turn, shared traits (some of which we don’t always associate with leadership). The traits are:
Doggedness. Captains just keep coming. Their example causes the rest of the team to raise their effort level to match.
Edges. Captains play right to the edge of the rules. (This is why he says Derek Jeter didn’t see many World Series trophies–too law-abiding.)
Carrying water. Captains do the dirty work nobody else wants to do. Many are not the most skilled player. Even if they are (like Tim Duncan), they don’t show their skills unless it is necessary.
Communicate. Captains communicate with everyone on the team. Sometimes this is vocal, sometimes eye contact, sometimes physical contact.
Displays. Captains make gestures for the team to see, like committing a hard foul.
Uncomfortable truths. Captains communicate things no one else dares communicate, in whatever way, in whatever medium necessary.
Regulate emotions. Captains play with emotion but they know how and when to keep a lid on it.