Originally Posted by
gns 
I don't think she would have asked anyone else - why does she think she can dump the late project on me?
If you're right about that, maybe it's because you allowed her to take advantage of your good nature in the past?
Doesn't really matter either way. Good for you for standing up for yourself and not allowing her to dump last minute projects on you just so she wouldn't have to work late.
Don't feel bad about saying 'no.' You are NOT responsible for her reaction to the fact that you stood up for yourself.