You're up to your neck in work while your co-worker complains that she's bored. When approached by your boss with another task you can do with your eyes closed but simply don't want to keep you at the office all night, are you able to say no? What about when she asks you to check in while you're on vacation?
Some of us are eager-to-please yes-women, while others are able to say some version of no when we feel it's appropriate. Do you have trouble saying no?