It's one thing to ruin a slab that can be sealed.  

Can be decent cash flow for rentals, but that's mainly because houses are pretty cheap.Mainly, I bought the one that I own because I had an old friend from high school in an abusive marriage, and her husband had ruined her credit so she couldn't get a place except for ones that would've made her leave her dogs.

In the 90s Mom and Pops were setting up S-Corps for tax and liability reasons and just ruining them same as they always had, without board of directors meetings minutes of meetings ect. so that's where the therm piercing the corporate vail came from. 

In flipping, you are most of the time dealing with larger projects hence a larger delta between the budgeted amount and the actual amount could ruin a project. 

High turnover and if you get one bad tenant it can ruin it for everyone in the whole property such as one tenant that lets their dog poop in the yard that doesn't clean up or brings in bed bugs that spread to other apartments or is just a bad character tenant where others don't feel safe etc.

Protected island with locals that lived there for generations instead of the influx of desperadoes ruining Playa Del Carmen. 

I have some airbnbs, and for now I have created the mails and the phones for each one, but it is a whole process proving the identity of the host as I have to give him his account with the new mail, and guide him through the steps of verifying (ID and selfie) each time.I believe it’s ruining the image of us as a property management company and I would like just to take care of everything and  not bother them with that.

Now you've gone and ruined it.

I've been out of commission for the past two years or so because of a divorce, but then my wife passed away of breast cancer, thus no divorce.

How have you navigated that without ruining or damaging the personal relationship?