Fortunately, my first high school teaching experience was at my alma mater. When I was hired, a toxic leader was on the way out, and a veteran AP grudgingly assumed power. She was just what the school needed. She embodied professionalism. I had the opportunity to work for someone with realistic expectations which were effectively communicated and modeled.
Afterwards, I taught at five toxic schools, back-to-back. The people in the highest positions had the least experience in the classroom; yet, they were responsible for making the most important decisions. Expectations were constantly changing, and I personally never witnessed any positive role-modeling or professionalism from those in leadership positions.