Another example I have... A friend of mine works for an employer who is open 365 days a year. (She works nights. 30-ish hours a week...) The rule was they can have Christmas off or new year, not both. She chose Christmas, and was due to be off 22nd, 23rd, 24th, 25th, 26th, 27th, and 28th December. Not exactly a massive amount of time off. She was due in 29th, 30th, and 31st December, and 1st and 2nd January! All good.
The manager who signed the time off (in July) left in October, and the new manager revoked the Christmas time off, saying 'no-one gets Christmas off!' My friend said 'but we always work Christmas or New Year here, and I chose to work new Year.' He said 'NO. No Christmas time off!' but still expected her to do new year. She had her Christmas all planned and arranged and family were coming to stay, and he was telling her she must work all through it.
I remember a day when the fucking workplace would have downed tools for this kind of shit, yet 'managers' in many places seem to get away with it.
My friend went to see the GP around 13th December saying she was very low and 'down' and wondered if she could help her. Told the GP what was wrong, and she gave her 3 weeks off with depression. Turns out this 'manager' had revoked someone's new year time off too, and THEY called in sick all over Christmas and New Year too.
SO.. the stupid twat of a manager had to cover ALL the Christmas night shifts (AND New Year ones,) himself as no-one else would do it. Couldn't do a THING about my friend being off, (or the other employee,) as they had a valid GP sicknote.
If he had allowed her - and her colleague - the Christmas/New Year they were promised (and that had been agreed by the previous manager,) he would not have had to cover it all himself, including nightshift on New Year's Eve.
I re-iterate. THIS is the kind of shit that makes people go 'off sick.' SHIT EMPLOYERS AND SHIT MANAGERS!