There is less monitoring and oversight of student progress in college. There is less control of student behavior in college. There are more curricular choices in college. College professors and students have more academic freedom. They also have less privacy to confer with students.
Greater value is placed on the unquestioned acceptance of the printed word.
High school education emphasizes the acquisition of facts with very little acceptance or tolerance of ambiguity. The focus is on transmitting existing knowledge. In college, faculty are more likely to create and transmit original knowledge and research. There are no study halls in college. College students often live away from home.