Needs More Sleep
I volunteered in the elementary school clinic for years and can attest that many parents send their kids to school sick.She sent us to school when we were sick. Period.
Part of it is that a lot of workplaces are more understanding of parents who are called to come and get their kids when the parents are at work than they are if the parents call in and say they have to stay home with sick kids. Which says a lot about those workplaces.
Part of it is that some parents think they are teaching their kids how the real world works--you have to go to work when you're sick, so you have to go to school when you're sick because that is how the real world works. Get in there and tough it out.
But most of it--and I am sure this does not apply to anyone's parents here, of course--was that the parent didn't want to be at home with a sick kid, often because the parent wanted that time to do other things. As in, have an affair, drink themselves into oblivion for a while, get high, or just not have to deal with the kid--to the point that a kid who came to school sick on a frequent basis or when several kids from one family came to school sick on a frequent basis, it was considered a red flag that something might be going on at home.
So y'all out there who send your sick kids to school might want to rethink that. The teachers hate you because whatever crud your kid has will infect the other kids and make their lives harder and the school nurse wonders what you are up to.