Here's a doozie from MIL! Basic background: my ILs own several rental properties, not horrible but certainly on the cheaper end of what you can get locally. Most have reliable, long-term renters, but there are always several at any given time rented by people who won't pay, are in the process of getting evicted, etc. I think they need to sell their cheapest houses and buy a few nicer ones and they wouldn't have that problem so much, but whatever

First half of the doozie:
Tenant Lady (TL) stopped paying three months ago. Eviction takes a long time - you get a month or so of grace period (if you have a good sob story), then it takes two months to work through the courts once your landlord pays the fee to start the paperwork. People who make a habit of being deadbeats know this, so they frequently just pay the deposit and first month's rent, then stop paying until they're evicted, at which point they've saved up the money for deposit and one month's rent on a new place. Many know to the day how long they're able to stay for free as long as they show up in court on the right days and make the right complaints. TL was one of those - she dragged the process out as long as possible, until finally the judge ordered her out. Right before she would have been evicted, she made an agreement to pay part of what she owed and to pay extra each month for the next several months to cover the rest.
Apparently she thought this meant she got another three months free, because she didn't pay any more after that initial payment. She was shocked - shocked! - to find out that the paperwork she signed for the agreement means if she stops paying, the eviction proceedings go right back to where they were, i.e. just a few days before MIL can call the sheriff to remover TL's belongings from the house. It's so unfair, MIL should have warned her, etc. Lady, if you want to rent a house, you have to pay rent! What's so hard to understand?
Second half of the doozie:
TL has a boyfriend (BF). BF has been living with her - in violation of her lease, which requires her to tell her landlords if anyone else moves in - and also living there for free. TL and BF have a fight, in which TL kicks BF out. BF calls my MIL wanting his money back. Yes, he was the one who put up the money to keep them from being evicted (the part that TL paid upfront). He gave TL cash, however, and since it was her name on the money order, MIL legally has to assume the money belonged to TL. MIL told him he could take TL to small claims court to get his money back if he wanted, but it wasn't her problem.
BF then decided he'd get back at TL and my in-laws by
burning the house down. He broke back in and doused the sofa, recliner, and living room carpet in kerosene and lit it. TL's teenage son was home at the time and managed to get the fire out, burning his hand in the process. MIL finds out about this when she arrives in the morning with the sheriff to formally evict TL, only to find a charred couch and recliner already out by the street. The neighbors told her what happened and that TL hadn't been back home since the fire but her son had gotten a ride to the emergency room.
So to top off a long story, MIL ended up calling TL and had to break to her that a) her son was in the ER, b) her boyfriend had tried to burn down her house, and c) her stuff was being put out on the street at the same time. TL was most angry about her stuff.
(I can't fathom why MIL and FIL do this voluntarily! Now MIL has to deal with fire inspectors, renovate the charred living room, and repair the smoke damage to the rest of the house, all before she can get any more rent for this place.)