I've had a great experience with my househack *knock on wood* This story is about my first tenant.
I had great tenants, but my first found out I was the owner and similar to my age - so he acted like I was one of his buddies, which is all good and fine but in the end, its a business. I had to draw the line at one point when he said something along the lines of "quit your bitchin'" when I had told him to make sure his driveway clear for the plows to come.
There was also a time when I clearly heard him having sex. Not sure if it was with another person or himself, but either way grossed me out LMAO
He ended up leaving about 6 months into his lease - which was fine with me - and I have had two awesome tenants since.
Thats really the only "horror story" I have - only other thing I'd mention was that there will be unexpected repairs (leaks, door handle repair, the proverbial clogged toilet, etc)
Hope that helps and you got a chuckle!