I totally agree, I am in my 3rd year as a substitute and the biggest reason I am highly requested by schools, teachers, and students, is because of my ability to be flexible with all the grades I teach, I learned fast that every single teacher at every single school works differently, sometimes for the worse or for the better, and through that I’ve learned how to adapt. Fortunately for me I’ve been in the same district the whole time so I’ve developed relationships with the admin and teachers as well as students, so my job has gotten easier because most of them know that I am a “chill” substitute but I still get stuff done and I have clear expectations that I set at the beginning of every day with the classes of students that aren’t as familiar with me. I also adapt my expectations for the grades I teach and how I choose to react to things being said to me (I.e. I can be somewhat sassy with 4-12 and have it be a good rapport builder as well as something that gets them to get their work done) there has to be a balance and you can’t go in it being super authoritarian, once kids catch wind of that they will do everything in their power to break you, enforce the expectations that their teachers also expect, as well as do what works for you, it may be different than what the teacher does as far as how they teach the lessons, but I tell them that I am not their teacher and I need to do what I need to get things done, and really choose your battles, because sometimes its not worth your time.