I am a student and I am " best friends" with a teacher. She has helped me a lot from, family matters, to grades, to drama, to even math homework. ( She is a reading teacher) I do not believe that we students should be discarded the right to be able to be connected emotionally to a teacher, your with them 5 out of 7 days a week anyway, might as well have a friendly connection with them.
Maybe it is better for teachers to have a friendly attitude with their students as opposed to an unfriendly attitude but of course they should not be too over friendly with them. If a teacher is considered friendly by his/her students then maybe the students will have better learning experience with that teacher and will earn better grades.
Any adult authority figure in our children's lives are under scrutiny in today's world, but this does not justify keeping children at arms length. Without a personal connection of some sort, education will be a simple exercise in rote learning. At some point the teachers must make some effort at being friendly simply to try to identify the basic identity and educational approach of each individual student. This is the only way in which a teacher can reach any students.