When my kids were in middle school and high school, I used to remind them at the beginning of every school year that the choices they make now will produce results later. Good choices (studying, paying attention in class, following rules) were usually reflected on their report card or at teacher conference time. Poor choices could result in a negative consequence--maybe a detention or loss of privileges.
The start of a new school year is a good time for all of us (students, teachers, parents, staff, community members) to remember that the things we choose to say and do NOW will have ramifications LATER. Let's think before we speak or act!