Religious Holidays

So my co-worker complains that she's been feeling tired lately, maybe she should see a doctor.

"Well, haven't you been fasting every day for Ramadan ?"

"Yes, not only that, but getting up every day before dawn for prayers."

This co-worker calls in sick for the last couple of days of Ramadan, which I assume involves some religious festivities?

But in the larger picture, in the U.S., Christmas is a FEDERAL holiday, declared in 1870, so lots of people automatically get that one off.