Hall monitor, shift lead, group admin: small power is where big character starts showing.

Small authority is where people first find out what power does to them, and the discovery is often unflattering. Very little is at stake, which is exactly why the behavior is honest: nothing is forcing it, so it reveals preference. Someone petty with a tiny role tends to be worse with a larger one. Someone fair with a tiny role has already been practising.

If you hold any small position, use it to make things easier rather than to be obeyed. Be consistent with the people you do not personally like. That is the entire test.