I love it when I get an email at work that says "MUST READ" in the subject line. It's usually sent by someone in admin. I just think it's so helpful that they tell me which emails must be read. Previously, I was working under the assumption that I should read all emails I receive. Obviously, this was an erroneous and inefficient method.
But let me tell you, I have seen the light. Reading only the emails that are marked as such has really freed up some time, time that I can use on more valuable pursuits like updating my blog.
My second favorite is when I get an email labeled "Please read" (also usually sent by admin). My first instinct would be to delete said message. After all, it doesn't say I MUST read it, so why should I waste my time on a non-essential? But that "please" catches me every time. I mean, if they can be so polite as to say please, then by golly I can certainly return the favor and click it open. I guess you could say momma raised me right.