My wanting to help out some young people (the first time) resulted in police on site for domestic abuse, social services checking on child welfare, non-payments and about $2500 in damages after they finally left (holes punched into walls, damaged carpets, etc)I'm not saying don't take a chance, but make sure the rental rate is not lower than the market (which attracts undesirables at times), and do your due diligence!  

Learn about neighborhoods, how to recognize desirable/undesirable areas. 

People with an undesirable history have a higher chance of repeating again.

Answer in the MLS, “Yes.”Computers cannot accurately determine whether a property is located in a desirable or undesirable area for a particular tenant pool segment using photos or aerial maps.

"Gentrification" is not wrong.A neighborhood is either desirable or expensive or undesirable and inexpensive.

Is there something bad or undesirable I should know about that type of commercial property.

Add in that it is now sharing a wall to the master bedroom which is generally undesirable and my guess is that it will not add value. 

There's also a vacant lot directly across from the house that is always overgrown, collects trash and sometimes undesirable visitors.

:D im currently looking into Brooklyn, east Williamsburg, Bushwick area.... the energy that made once undesirable Williamsburg a yuppies paradise seems to be continuing deeper in Brooklyn into these areas...

If it is not selling for what you think the market value is then is there anything particularly undesirable about this property (neighbor has three white vans in the front yard and dogs that bark all day and night)?