I think the anger comes from many causes. When period comes, we will always in anxiety worrying there might be leakage especially in the first 2 days. Over anxious will then make our emotion overloaded with stress. Some females may have serious menstrual cramp, it is very painful when they still need to come to office despite having cramp. They might want to have least interaction as possible, hence anything that prolong the conversation will trigger their anger. Scientifically, the hormone change during the period is like a roller coaster, it will cause emotional breakdown of no reason.

It is not easy to become a female. Therefore please respect and appreciate any females around you.