Hired a property manager, found a tenant, and did my best to be a good landlord. Let the tenant pay a couple of weeks late a few times without getting bent out of shape, fixed things promptly, etc.

Then the time finally came to sell last year. The market had recovered, I could sell the house and actually make a profit. My reward for doing "the right thing" (not defaulting/short-selling/etc.) was ready to be reaped.

Tenants moved out... got our first look at the house. It was a complete nightmare. Turns out they raised rabbits (as in, to sell) in the property and trashed the place (poop everywhere, stained walls, and egads.. the smell). Ended up taking a large loss on the property anyway - had to basically dump it in order to find a buyer and just be rid of the thing.

The tenants lost their security deposit. That's it. I lost tens of thousands on the sale price (and this was a sub-$200k home), not to mention the years of maintenance, etc. I spent (well, my useless PM charged me) while they were in the house.

Yea, should have just sent the bank the keys in the mail and walked away. In the end it would have been less painful.