My youngest brother got it at pre-school. Some of the mothers up the street wanted to send their kids to play so as to catch it (this was the late 70s). He basically had some spots and had to stay home.
It spread to may sister, who was first grade or so. Her case wasn't as mild, but was still basically a two week vacation.
She gave it to my 7th grade brother and 9th grade me. And *those* were another story.
My mother told me to stop complaining, because I could have it as bad as he did.
And the next day I was worse than him, and not by just a little!
She took my temperature at 105F, and somehow managed to get me to the bathtub despite my delirium and being much larger. [it doesn't take long for that tempt to do brain damage].
And after that, it was sit in the big living room chair, and try to find a position that didn't rub, and stay all day without moving.
It was reasonably consistent back then that the older the child, the worse the case.
And without knowing that a vaccine was around the corner, childhood chickenpox was about the only protection against adult shingles (and oh so far from perfect!)--thus the mothers wanting to send kids to catch it!