How is this the only post that mentions the chalkboard screeching? That noise was the bane of my existence in school. Maybe I'm just more sensitive to it than most, but it would make my skin crawl for the rest of the class, and if there were someone inexperienced using the board and producing considerable squeals, I couldn't focus on anything and had to restrain myself from just getting up and leaving the room.

If for no other reason, this makes whiteboards a godsend.