If you are a landlord long enough, you will have tenants that just don’t seem to have any common sense when it comes to maintaining a property.  And I love the fact that they always claim that they didn’t do anything wrong.  No ownership of the problem.  This landlord gives a great account of one such tenant interaction:  http://www.realestatewindfall.com/2010/01/05/plumbing-problems-by-careless-tenants-how-to-handle-them/