Middle school kids are a different breed. If you aren't motivating them, they are not learning. In fact, they are probably tearing something up if motivation isn't in the picture. During my years as a middle school principal, I figured out that building a school culture with character education, fun, and a sense of belonging was key to improving student achievement.
The year before I arrived at a junior high of 510 students, teachers sent students 5,090 times to the office for disciplinary infractions. Discipline was handled in three different ways: kick the kid out, let the kid sit on the bench outside the office and go to their next class with no consequence, or paddle them. The school board was very adamant that this building culture change.