Like it or not, teachers are role models.
If the only valuable thing that your students learn from you are the facts of your subject matter, then you have failed as a teacher. That's right, I said it. Failed.
You have 180 days (or some other significant amount of time) to prepare your students for the future.
Model good manners, respect for others, and professionalism and you will be helping your students much more than if you just taught them facts from a book. Take advantage of the time you have with them and prepare them for more than their next class.