Things go wrong in most stories. It would be a dull plot that did not include an upset, a setback or an obstacle.
But it takes a special kind of reversal to turn one of these plots into a black comedy. Often it's a tiny slip that becomes a vortex of disaster; sometimes it's a growing avalanche of humiliation.
But it's always hewn from the stuff of everyday life, which we see transformed into a minefield using only the slightest shift in perspective. And it allows us to laugh while giving thanks it's not happening to us.