As suggested above we each develop our stereotypes based on our learning environments.
I thought I would mention that teachers also develop stereotypes about students, based on experiences. Remember a stereotype is created when you make an assumption about a large group based on a single experience or no experience.
Teachers often stereotype based on looks. We think girls are more academic than boys and "clean cut" kids will behave and perform better. We often think athletes are poor students and artistic and creative students are smarter. NONE of this is true. As you yourself know, we are each individuals and our strengths and weaknesses cannot be seen on our face or often even in our transcript. (i.e. Should coaches assume all tall kids are good at basketball?)
Perhaps you could consider how your own teachers, administrators, coaches, etc stereotype you, and your friends and classmates and in return, how do you stereotype them? Do you make assumptions based on age, gender, clothes, looks, ethnicity or even subject matter taught? (i.e. Should students assume that all P.E. teachers are not good at academics?)