Courtesy of Mr Wizard:

When you send me an e-mail on Monday morning saying I haven't fixed your issue in the 4 days since you reported it, it's not really appropriate to include the 3-day holiday weekend in that 4 days. I realize that since you graciously CCed my supervisor you needed to make make it sound like I've been ignoring you forever, but think about the fact that I've only had your issue for *2* business hours before you go spouting off.