difference between the fake email and the email etiquette.

So what is the difference between the two emails we did. I am not to sure. They both had to be long. And we had to talk about a bad grade in class. So you tell me whats the difference.
We had two assignments to do in our English class. First one was the fake email to a friend, second was the email etiquette to the teacher. They both had to do with having a bad grade.
The fake email we all had to write on our blogs were to a friend. Which i wrote mine to my baby daddy. I value his opinion higher than any one else's. Which is weird i know. Any who, in the fake email I can act who i am. To be my self. Not to worry how i sound. Of course I do want to make sense and have my spelling right. But it does not have to sound right at all times. The language is also not important. You can say words you would not normally say to a teacher. No one would care.
The other assignment is email etiquette. Which we had to type up on paper. When in the email etiquette i have to sound mature because your writing to a instructor. Make sure my spelling and punctuation is correct. Which we all know i do not pay attention to any of that. And in this you cant just talk like you are friends. You have to get to the point and make sure its understandable. Instructor don't want to get bother by nonsense unless there a really cool teacher who wouldn't mind a chat. But otherwise no. It was hard to do this one. I mean I would feel embarrass if i was actually writing to my instructed to change my grade. I don't think i would do such a thing. So trying to come up with this assignments was new thing for me.