I was in the office today setting up a few machines when I came across one of our newer PCs sitting alone under a desk. This note was stuck to the top (actually, the underside because it was upside down) of it:

Hey, thanks mysterious co-worker!  Thank god you were able to not only leave a note but describe exactly what the problem with this machine is.  I’m actually impressed that you are so technically inclined.  My hat is off to you, sir or madam.