We've given up explaining these people

So, if you feel you can't go to work on a given day, what do you do?

What's that you say? Call your boss/manager? Call the specified "call out" line? 

You mean, you don't send a text or a Facebook message? And not even to your boss but to a subordinate? Because Mosquito seems to think this is perfectly acceptable. 

And to make matters worse, the excuse she gave? "I stayed up late last night. I'm too tired." Most places you don't even have to give an excuse. Just "I'm not coming in today". If you feel the need to give a reason why not stick with "I don't feel well." "I'm too tired" is only valid if you were at the emergency room or something.