A snake once got into a man's friend's house. Everyone suspected that the snake got in through a crack in the foundation. The man hated snakes and grew fearful that one might enter his house. So, he carefully checked his foundation and ensured that all cracks were well sealed.
Then someone said, a snake would come in if there was any chance a rodent could get in. So the man sealed every crack he could find from the foundation to the roof and he felt safer. Then someone said, birds could get in through the chimney. Birds carry disease, people said. So, he covered his chimney with screens.
Then a poisonous spider bit a neighbor and he became very ill. Somehow it had gotten into his house. They suspected the spider got in through a vent or maybe through the screen in his chimney. So, the man sealed the vents and his chimney. Nothing was getting in. Through the summer - no snakes, no rodents and no spiders. He was very happy.
Winter came. They found the man dead in his house. It wasn't a snake. It wasn't a rodent. It wasn't a bird. It wasn't a spider. He had sealed his house so well, it filled with CO2 and the air killed him.
The moral of the story is that we can become so obsessed with potential enemies that we kill ourselves with our own solutions.