“At the door of every contented, happy man somebody should stand with a little hammer, constantly tapping, to remind him that unhappy people exist, that however happy he may be, sooner or later life will show him its claws, some calamity will befall him—illness, poverty, loss—and nobody will hear or see, just as he doesn’t hear or see others now. But there is nobody with a little hammer, the happy man lives on, and the petty cares of his life stir him only slightly, as wind stirs an aspen—and everything is fine.”
Checkov’s short story “Gooseberies”

As in that old Checkov story,
We like the hammer man to

Stand at happy door to tap,
Tap to remind a man inside

Of the worse times to strike,
Of calamities to befall later.

But the man inside the door
Continues to be contented.

There looks like no hammer
To tap away his happy door.

And we are rather unhappy,
Deprived of delicious irony.