Whats wrong with your teacher being your friend?
I still regularly talk to my year 11 science teacher 4 years on, got a picture of her with me and my mates at prom on my wall, she's in her 50's but an out and out legend anyone in our school will tell you.
Part of what made her a good teacher (aside from being incredibly knowledgable in the subject) was her friendly nature, use of comedy and you knew if you got a *******ing it was going to be loud and you'd feel bad for disappointing her.
Seriously the best teacher I've ever came across, did triple science GCSE and absolutely destroyed it with her help.
People are so quick to dehumanise education and embrace the standardisation we are seeing increasingly within schools these days, but quite frankly it doesn't work, we aren't robots. We are all people here so why shouldn't teachers and students be friends? Hell I think it's stupid not to be, how are you able to effectively teach someone and know what works best if they're just another name on the register?