It usually goes something like this. Bob or Suzy sign up for some cause which they are highly enthused about. They throw themselves into it with great gusto and believe (unfortunately) that they are doing the "cause" and everyone else a huge favor by joining up. Because of their gusto and enthusiasm, they will rapidly reach a level of quasi-authority, either by self-appointment, or by default and in doing so, they will assume airs. Their new found position will involve organizing, bossing around others or generally being a busy-body.
All will go well for a while until one day something happens. Someone will tire of their officiousness and tell them to take a running jump, or they will not receive the respect that they believe is their due.
Bang!! The door slams shut behind them and they're gone as quickly as they arrived. Before you know it, they're at the church or club down the road, busily telling anyone who will listen what a bunch of S.O.Bs they all are at the other place.
Sad. Human nature doesn't change.
Life goes on Jim, is the bottom line I guess.