Recently, there's been a plague of flies in your home. You've tried sprays, sticky paper, and even just letting the spiders move in, but no matter what you do, they never seem to leave. Finally at your wits end, you call an exterminator to settle the matter once and for all.
He arrives the next day and has a look around the house. After a cursory search, he tells you that something in your basement is attracting the pests. You both go down to investigate.
The rank odor you had long ago adjusted to and all but forgot suddenly becomes a hundred times stronger as you both go down the steps. The source of the smell becomes apparent halfway down.
It is a body. Its limbs are twisted at odd angles, and it is swarming with maggots. It is at least several weeks old.
The exterminator turns and runs up the stairs, obviously trying not to vomit. A moment later you can hear him dialing the phone, calling the police, but you can't bring yourself to care. Staring down at the corpse, you suddenly feel very far away. The last coherent thought you have before fading into nothingness is;
I can't believe I forgot.
You'd think that falling down the stairs would be something you'd remember.
It really was careless of you.