The thing about the corporate world is that everyone is dispensable, no matter what. But many of us have worked under bosses who think otherwise. They are probably intoxicated by power and believe that no one else can take their place or do their work.
And so was the case with the boss of Reddit user Milled_Oats who strongly believed that nobody was capable of doing her job. And when the original poster (OP) offered to fill her role during her absence, she snubbed them. Well, they complied maliciously after that and the boss got swamped with work when she returned three months later!
More info: Reddit