At a minimum, the environment needs to be predictable. Whatever systems are in place, they need to be executed consistently and fairly. This includes both the harshest and most permissive learning environments. The rules need to be clear and fairly and consistently enforced. All participants (students and teachers) need to be treated consistently with respect.
I believe (somewhat controversially) that this includes understanding that most students will not thrive with boring and/or seemingly irrelevant coursework. This is where constructivist pedagogy particularly distinguishes itself. Allowing the students to construct their own knowledge, making it more durable, more relevant, and more fun.
I also believe in a risk taking classroom. In such a classroom, the students dare to be excellent and learn to cherish their mistakes. Being wrong is on the road to being right. Included in this is the humanity of all participants, their desire for inspiration.
One of my most basic philosophies comes from William Butler Yeats: “Education is not the filling of the pail, but the lighting of the fire”.