It also convinces users by saying something along the lines (to the computer)... "Either work or you'll be a boat anchor". The look as I've walked away is priceless.
Sidenote.. I had a poster in the lab/shop with a voodoo priest on it with the words: "Computer fixed. No chickens needed to be killed... this time". I retired, left the sign and from friends still there, the poster is still hanging in it's spot.