Teacher doesn't like those hugs... ?

I find this much hilarious! I have spoken that the boy and I hug when we leave each other for our next class periods, am I right? After gym period, we walked the short, little way to those classes, and his locker is first, so he gave me a hug (which we both know we want long hugs.), and my homeroom, science teacher was literally right behind us when we hugged, and what came from her mouth was, "Uh-huh. No. No." I like my teacher, and I respect her completely, but what my voice reflexes wanted to respond was, "Mm-hm. Yes. Yes." I realize school rules are there for a reason, but what's with the "no-touching"? All it is is a simple, harmless hug - there's nothing wrong or inappropriate about it. Not one thing! But I still feel the same way for my teacher as I have when I first met her. She's very kind and funny, and she quite understands.