How to email a professor

Stumbled across this post today - all about the act of emailing a professor and the norms that should be adhered to. I always get a kick out of my students addressing me as "Ms Nellison." I see this as a cue that's given off -- evidence that they perhaps haven't looked at the syllabus but rather are only responding to emails from me. And signing one's name and class is always welcome - I've received a few emails from such cryptic characters as "hotbuns54."