I have a better one.
This actually happened to me.

While waiting for your OAK-SEA flight on a certain Dallas based airline, you learn that the aircraft has gone mechanical.

You are a savvy nonrever and have back up tickets.

Instead of joining the 100+ passengers in line hoping to re-book, you see that a certain Alaksa based airline has a flight leaving in 20 minutes. You run over to the gate, where the smiling agent says "sure, we have plenty of room".
Soon, you are on your way to your destination while all the paying folks are waiting to be accomodated.

I love the flexability!