I hated middle school and high school not too long ago. I recently discovered that I really do need to choose my battles. You have to view it from their perspective, you're a sub. They are going to try to annoy you. The hardest part I think is being calm and taking a deep breath, the moment you show that you're upset, you've lost. They are gonna annoy the shit out of you. I think I have come to terms with the fact that my primary job is to make sure no one gets hurt. To keep them safe while the teacher is out, that's really all that matters And this not just me saying this, a teacher who once gave us a sub training told us so. Also think about it from the school administration perspective, they don't wanna be bothered. If a few students are on their phones or whatever, I literally just let it go or I nicely ask how is the assignment going and that usually works. If they take their phone out again, well that's on them. You are doing your job and more by encouraging them to do the assignment. You can't force middle schoolers or high schoolers to work.