Countless times while commuting, there would be a simple delay earlier in the day . More than a few times, I've heard the agents telling families on vacation that, because they missed their connection, the soonest they could confirm them was several days hence. As much as I can't stand the thought of gov't screwing things up, I'm amazed the airlines can get away with this sort of thing.
I mean, if airlines are supposedly SO VITAL to the transportation system (i.e. the supposed reason we are still under the RLA) there SHOULD be enough capacity to cover issues which are entirely foreseeable. There will ALWAYS be weather, maintenance, ATC delays and cancellations. And, as long as airlines run tight on staffing, crew delays and cancellations are inevitable as well.