Because, you know, love isn't all romantic. There is love between parents and their children, love between friends...
Now here are my thoughts on the subject.
I suppose it all depends, of course, on the particular teacher and her level of comfort with the idea. Some might be too scared to try it and others might be like, "go for it!"
Some other points I feel might strongly affect this situation:
- The law: Obviously, it can't be against the law where you live. Luckily, where I am it's considered weird but legally OK.
- Friendship ONLY!: I'm not saying anything beyond pure, innocent friendship! That's just wrong, IMO, unless the students are in college and very close in age to the teachers; or at least very mature people.
- Benefits: Students should get no benefits from the friendship, i.e. extra points or whatever. If they're friends with a teacher it should be for the same reasons they'd be friends with anyone else: they like them as a person. They should keep work and friendship separate, which I know can be tricky, but I think my teachers and I have managed it pretty well.
- The way it looks to other people: Generally I find that same-sex friendships are more acceptable, but then that may vary from person to person, so...
- The principal: S/he should be aware of the friendship so it won't seem fishy. Also, I don't think the teacher and student should be secretive about their relationship because that might give the impression that they're trying to hide something.
- Ages: I guess a middle-school, high-school or college student might be OK being true friends with a youngish (40-) teacher; perhaps not as close as friends the same age, but still. However, I don't think an elementary-school-aged kid could--or would even want to--be a teacher's friend.
- Respect: No matter how friendly they become, the student should always remember that their teacher is not their age and they should respect that (call them "Teacher" or "Miss/Mr. [their name]", for example, not by their first name. And I believe they should of course not try to roughhouse with their teacher the way they would with other kids their own age.*
I speak from experience, here. Two of my teachers I am really close to. One was OK with us being friends until I had a problem with another teacher who, since she is the principal's pet, got off scot-free after 'playfully' strangling me and then lying about it; now she says we can't be friends, but I get the impression she's just scared to lose her job. I'll see what she says once I switch schools at the end of this year.
The other teacher is a very special person. She and I are friends on Facebook, we chat via e-mail and by phone. She has told me that I can call her to chat whenever she likes. She has always supported me, and she actually started hugging me before I started hugging her. Since she has now earned my complete trust, I told her about the other teacher, and asked her outright whether she thought we could be friends, and she said, "Of course, honey. I can understand why [the other teacher's name] might be scared, but I'm different, and I love you." <3 ! She's also one of the few people at my school who can speak good English. She's so smart; she speaks French too, has studied in two other countries, and she's getting her master's degree in mathematical philosophy. I think she's easily the most intelligent person I've ever met. I love her so as a friend. I'm going to invite her over for dinner when we're both free from work and study. We're so alike, it doesn't even really matter that she's over 20 years older than I am.
*This even though one of my former classmates (he's left school now) used to jump on the physics teacher and try to throw him to the floor, and as a consequence got kicked playfully out of the classroom. God...I was so shocked when I saw that! Another time, a classmate--this huge girl one year older than I-- picked up my tiny geography teacher practically by the neck because she was mad that the teacher exposed her lack of knowledge on her subject. The teacher only mildly told her to put her down, but it made my blood boil!