Almost every single teacher that I have had I have been great friends with. It opens up a lot of things that could be talked about. It also gives the student another person that they could go to and trust. Relationships should never be romantic between students and teachers no matter what the age is. If a student has no one to go to and talk about their problems then they could go to their teacher.
Teachers who get too close to their students lose objectivity and begin to favor those students over the other students in the class. It's fine for a teacher to be friendly towards their students but they should always keep it at a professional level so they can teach the class properly.
No, teachers should not seek out relationships with their students, because it is better if the teachers maintain a professional relationship with students. So many teachers take relationships with students too far, and behave inappropriately. Students should just attend their classes, and both sides should avoid personal relationships that can cause problems.
Apart from a professional relationship, teachers should not seek out relationships with their students. Teachers should not be romantically involved with their students. Even if the student is over 18, it is still inappropriate for a teacher to engage in any type of physical relationship with their students. If teachers are involved in romantic relationships with a student, then there is the possibility that they may give that student higher grades.
I think that personal relationships between teachers and students is very inappropriate. Not only does it bring up the possibility of biased grading, but it is also unethical. There's a reason that teachers usually aren't allowed to teach their children and relatives, and that's because it gives those kids an unfair advantage over others.
No matter what the age difference is, it is improper for a teacher to have a social-romantic relationship with a student. The teacher is in a position of authority over the student, either directly or indirectly. Any teacher-student relationship should not be considered while the student is still in the school system.