Today I subbed for a middle school English/Science teacher.
Today was also the first day back from spring break. Saying that the kids were wired would be an understatement.
While the relationship isn't one-to-one, there is a strong corelation between a teacher's level of classroom control and how those kids will act for a sub. This becomes even more obvious after you've subbed in a school a few times and have worked with the same students many times, just with different teachers. A group that might be angels in, say, History, might be total terrors in, for example, Science.
Also, when the lesson plan reads, "Have students reply to the prompt: 'What did you do over spring break?' and then have them share to the class," perhaps it is a good idea to preview what the kids are about to say, before you let them say it...