OR - you confront her. At this point, I'm curious. Does she have a disease like MS that caused her to drop the paper, but we are seeing it as hostility? She certainly has a "life is short" attitude, that is not necessarily a bad thing. But the cyclical nature of her extreme crabbiness makes me think PMDD - I used to have a happy face / sad face indicator like you put on the dishwasher to show if the dishes are clean or dirty, only I drew mine on a paper plate, and the guys I worked with used to flip it over as appropriate, then run! (if flipping to sad side - except that always made me laugh)