Power
You'd think you would be able to wheel and deal like Willie Stark and do whatever you have to to keep your tenants happy and your rental units filled. You have the word "manager" in your title, after all. But, sadly, this is not the case. Many apartment complexes today are owned by enormous property management firms, and it's corporate who gets to make all the decisions, not the person who's actually on the ground and privy to the sit rep.
For example, say you have a family living in Apartment 12-101. They're nice people: The dad's in software, the mom's in graduate school, and they have an adorable nine-month old daughter. They, however, have a problem: their upstairs neighbor.
They've lodged multiple complaints with you, the property manager, about this guy. He plays the radio too loud at night. He drops cigarette butts all over the family's porch. He screams verbal abuse at the young woman who lives with him…a young woman, it turns out, who isn't on his lease. The family has even called the cops about this resident.
The family in 12-101 expects you to do something about the situation they find themselves in…but you can't, at least not until you've talked to corporate. And, as it turns out, corporate is less than sympathetic to the family's plight: Word comes from up high that they can either move to another unit in the complex, or be released from their lease at a cost to them of $1000.
The family opts to pay the $1000 and take their business elsewhere. They inform you, politely but firmly, that they will never rent from the property management firm that owns your complex again, and that they plan on sharing their horrible experience with their friends and family members.
So, there you are, caught in the middle, powerless to please the family in 12-101, powerless to get rid of an upstairs resident who will continue to be a nuisance to his neighbors, and powerless to convince corporate to do something decent for a customer.