It's the Principal of It
Sometimes it may feel like your principal is your enemy instead of your educational partner. If that happens, try to view the situation through his/her eyes. There may be issues going on that you are unaware of or maybe you are just wrong. If you consider all of these things and still feel that you are in the right, stick to your guns. Just make sure, that the primary focus is always about the students and what will be of benefit to them.