I think what dionidium was getting at was he only had about 20% of the story and filled in the rest in an uncharitable way. If dionidium is not the manager of that employee, dionidium does not deserve or require an excuse or explanation. If they are the manager then this complaint shows a lack of management skills and/or poor office culture.

"I'm feeling sleepy and will be in later" is an employee being upfront and direct that they will not be productive and do not want to be the source of waste in the office. This is an employee that should be rewarded and encouraged. An office culture where this type of message is ok should be encouraged.

What you don't want is a toxic culture where everything needs to be explained and justified to an office full of scorekeepers and clock watchers. The people that do care are the ones that shouldn't care and should probably be minding their own business.

In dionidium's scenario it is very possible that employee worked it out with their manager and the message was a courtesy message. It is very possible they are tired from putting in a late night the night before. It is very possible they are tired due to "truly unforeseen and unusual circumstances." Etc.

To me, dionidium is the problem in this scenario.