I worked at a school and it always seemed that once you have established your lesson plan, it'd be a pretty easy and fun job. >_> Now getting that lesson plan down could be tough, I'm sure. But they tended overall not to move people around to different classes often at the school. I'm sure sometimes there is work to do at home but they also seemed to have a decent number of breaks--in elementary, kids going to recess or gym or lunch or band or computer class, and most middle and high school teachers had a couple free periods and a couple study halls. Maybe the school I worked at was an anomaly, though.
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https://imgur.com/09qFfLV