This property manager was so sneaky about trying to keep this young couple's security deposit. He had no idea who he was messing with! If you've ever rented, you're probably familiar with the concept of security deposits . On top of paying your first and last month's rent, your landlord will probably hit you up for that deposit. A lot of people just eat the cost, knowing that they'll be putting up shelves or painting or otherwise causing “damage” in their apartment (we all know it's not really…