This is the story of why I had to get two cats.
I had always been raised with animals. As I was growing up we had, at various times, gerbils, dogs, cats, and a monkey. When I moved out and went to college I was of course petless. After college I lived in apartments and remained petless since I worked crazy hours and had no one to help me take care of them.
One day I came home to my second story apartment to find a kitten in the middle of my living room! I had left for work at around 5am so I thought maybe it had walked in as I walked out (my eyes were not always open at 5am).
What to do? I thought of putting it outside, but could not bring myself to do it. What if it was lost? It had no collar. So I went to the store and got all the essentials (litter box, cat food, etc..) and realized I now had a cat.
The next day I came home---NO CAT. I searched my entire apartment fearing that it was trapped somewhere, called the apartment manager to make sure no maintenance people had been in my apartment (the apartment building fortunately did allow cats), I was very sure he had not walked out the door that morning. Several hours later the cat appears walking down the hall and wants loving and food. I figured it was an exceptionally good hider and forgot about it.
This scene repeated itself for almost a week until I discovered the truth (just in time to save my sanity). There was a small hole cutout under my bathroom vanity for maintenance. "My" cat was actually my next door neighbour's!! She was away on a trip and had people coming in to feed her three cats. My little guy got lonely (it was an exceptionally loving cat) and had found the hole under her vanity crawled in it through the walls to my apartment. During the day it would go back to her apartment to be with the other cats and to eat the food there. At night it would come to be with me and eat my food.
Two weeks later my neighbour came home and I let her know what had happened (curiously she had named the cat Shadow). I was in love with the little thing and had hopes she would say I should just keep it. No such luck, she apologised and blocked up the hole under her vanity.
The next week I went in search of two cats, but that is another story.