Noticing when someone is on their period
Very important when dealing with people is knowing when it is the time of the month that they get easily frustrated and start ranting when the slightest thing doesn't go their way.
The most important thing to do though is not point out that said person is on their period as they don't like having it pointed out that they aren't in complete control of their senses.
Just simply nod and smile and avoid confrontation during their period and once it passes you can take the moral high ground and remind them of all the stupid things they did in the previous week.
Oh - hello Tomkat