How to tell a teacher I respect him and appreciate what he does?

Hey guys, just a quick one :)

There is a teacher (no, I don't fancy him/ love him etc) but I do really appreciate him. He is such a lovely guy even in class and we have had a few out of class discussions. We get on well, but I am nothing special to him really.

He puts so much effort into teaching my class but all they do is F about and put him down and quite frankly take the P out of him. He gets so exasperated with our class and it seems like only a few of us pay attention, but it seems Im the only one who respects him. Teaching teenage girls is a hard job for a guy like him.

They completely disrespect him and I know that it can annoy him quite a bit, but he is still good to us and still teaches us. He doesn't get angry because then he knows it won't help anything, so I guess he's a little trapped.

I really want to find a way of telling him without sounding like a teenage girl that's obsessed with him. Okay, yeah, I moved to his class about a term or two ago, but that's because he is a brilliant teacher (class mates have... Other ideas) so if I say anything then he would probably think I'm clingy and desperate, which I'm not. I respect him a lot. Teachers in general put effort into the powerpoints and lessons and activities etc, but for only a few teachers seem to get any respect at all from the class and it's very weird because I go to a grammar school, ad you'd've thought we'd be more sensible. So how can I go about this? I'm really, really stuck. Xoxo, thanks in advance