Categorizing behaviors and having a plan to consistently handle them is vital to the management of a classroom. Whether it is kindergarten, fifth grade, special education, or high school, as educators we must be able to manage the behaviors in the classroom to ensure effective education. Behaviors can break a classroom as disrupt the education process of every student in the room if there are not rules, procedures, and consistent consequences, behaviors become the norm and can escalate. For teachers that do not have effective classroom management skills and utilize consistent consequences, undesired behaviors can become like a domino effect. As you said, students will run a muck. If one student talks repeatedly out of turn and the behavior is ignored, everyone suddenly thinks it is okay and before you know it several students are talking at once. Something as simple as getting out of their seat randomly and walking around the room, can be a huge distraction. As teachers, we have to have control of our classrooms in all aspects. Expectations must be laid out clearly and concisely so that students understand what the consequences are. Minor behaviors can escalate into intermediate, and intermediate can escalate into major behaviors. As you also said, things must be handled immediately.