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The minor injury turns into a fatal illness. His wife, his colleagues and his doctors respond with evasion and irritation, and the only person who comforts him honestly is Gerasim, a peasant servant who holds up his legs. After three days of screaming he realizes his life was 'not the right thing', feels pity for his family, and dies free of the fear of death.
A life organized around what is 'agreeable and decorous', meaning correct career moves, fashionable furnishings and approved opinions, can be empty precisely because every choice was sanctioned by others and none was examined. It is terrible because it is ordinary: nothing marks it as wrong until death forces the question of whether it was lived rightly. By then the conventional markers of success give no answer.
Everyone around a dying person agrees to pretend he is merely ill and will recover if he follows treatment. This shared pretense protects the living from discomfort, not the dying from pain. It leaves the dying person profoundly isolated, while one person who openly acknowledges the truth, as Gerasim says 'we shall all of us die', offers more relief than all the medicine and manners combined.
Knowing that death is universal as a fact is completely different from grasping that one's own particular self will end. That gap is what lets people postpone every question about how to live.