In preschool, they decide when school happens because they have you by the toddler balls. They don't follow a regular school calendar, because fuck you, they do what they want, this isn't real education yet. The "pre" in "preschool" does stand for "pretend," after all.
This isn't to say that your children aren't learning. Preschool is absolutely preparing your kid for real school, teaching them social skills and how to count and read and be good human beings and all that. It's necessary, even if it feels like it exists because you need your toddling, sticky-handed, Frozen-song-on-repeat-singing kids to go somewhere for four to six hours a day so that you have the patience to survive the Infant And Toddler Crying Face Off Everything's Wrong Hour, aka Dear God What Have I Done To My Life Minutes, aka Sweet Sally's Shit Show, known to the rest of the world as 6 p.m.
Plus, you have work to get done during the day. And since someone decided we're legally not allowed to carry children around with us in a zipped-up backpack all the time (even if you do adjust the straps on your body properly and pack snacks in there), we all needed another option. So, someone invented preschool.
But then they realized what an amazing invention they had. They realized they could charge whatever they wanted for it. They realized they could come to work whenever they wanted to, or didn't want to: They just had to make up the right holidays for it. "Welp, looks like there's no school Friday, in observance of National Grated Cheese Day."
And then there are the snow days that we take off of school because of one snowflake. I'm convinced that Pete Delkus and preschool are working together to forecast these pretend storms just to keep kids out of school. "How was your snow day!" they all ask, in a singsong Caillou-happy voice. IT WAS GREAT PLEASE TAKE MY CHILD BACK. I HAD AN EIGHT-HOUR NIGHTMARE THAT "I'M A LITTLE TEAPOT" WAS PLAYING ON REPEAT AND I COULDN'T WAKE UP AND THEN I REALIZED IT WAS 4 P.M. AND I WAS NOT ASLEEP MAKE IT STOP.
Hug your teachers. Pay them more. And always remember: If we were forced to be around our wonderful children all day, every day, until they were 18, the human race would surely become extinct, and the robot preschool that remained would probably take a month or so off, in observance.