...done a few years ago found that playing Xmas songs over the office P.A. was the most depressing thing you could do in an office.
We (that is, the I.T. Dept, all three of us) tested this one year (I worked in a rural council) when the CEO asked us to put Xmas songs over the P.A.
On the first day, it was pretty much ignored.
On the second day it was shut off after 2 minutes and twelve seconds (someone yanked the power on the amp.)
On the third day, the CD player mysteriously vanished (it turned up in Janurary).
We tried plugging in a PC, but it's amazing how those things eat power cords.
On the fourth day, the CEO decided that playing Xmas tunes was probably not the best thing and rescinded his original order. His decision may have had something to do with the sixty-seven written complaints he received after our final attempt at filling the original order (iPod, set to shuffle and repeat, volume on amp turned up full to overcome local volume knobs, and the whole thing locked in a cupboard.)
Funnily enough, our office wasn't connected to the P.A. system...
(true! we really did this!)