Years back when the company I was working for got individual PC's for each employee.....at one time we had one computer PER FLOOR which was mostly used for word processing. We might of used it a bit to enter budget figures in, but not much.
When I finally got my own computer in my office I was so excited. We had to attend many classes on how to operate it and I felt fairly confident. One day I called our IT dept and had a technician come in to see why I could type stuff out but it wouldn't show on the screen BUT I could print it out.....she worked and worked. After a while she collapsed in laughter until she cried.....I had changed the font color to WHITE, so I was typing WHITE on WHITE and it wouldn't show on screen, BUT could be printed. We laughed so hard that we had folks from other offices coming to see what was so funny...I still laugh at that. BUT I've never pulled that same trick again !