Wearing the captain’s armband shows the team who you are when you finally have a little power.

A small amount of authority shows people what you would do with a larger amount. The role does not change your character, it only gives it somewhere to act. Some people use a position to be useful and some use it to settle scores, and both tendencies existed before anybody handed out the armband. What people learn from watching tends to stick.

If you are given any authority, decide first what you intend to use it for. Spend most of it on whoever has the least standing in the group. That is the part people remember years later.