My current show has had, well, some difficulties. Putting in understudies last minute, a bout of food poisoning mid-show, replacing an actor, some diva fits, etc.
It's April Fools, and while I have a good sense of humor, it is NOT the day to tell me you're going to be sick, won't go on, won't let so-and-so do your costume change, etc. Because there's the chance you aren't kidding.
One of my actors jokingly asked if stage managers can take jokes, since they always seem on edge about things that could go wrong.
I think because we're so used to stepping in when things go haywire, it's hard to NOT assume the worst. Or maybe it's just me.