This is how it starts:
First you adopt a cat.
Then a second cat adopts you and starts living in your yard.
The second cat moves in.
Some cats move in across the road.
They become obsessed with gaining access to your home and spend every waking hour in your yard.
These two cats sit on the outside of your living room window sill and your two cats sit on the inside; they're all gazing out in the same direction.
You go outside one day and are surrounded by cats. Two from your house, two from across the road and a new comer who's fascinated by your home and sits in the garden watching it. You have the feeling that there's another watching from the bushes. But you can't be sure.
Congratulations! You now look like a mad old cat lady.