I helped out in a marketing agency for a couple of weeks and they were all using macs. They only had one single PC, but noone could even handle it. Some guy, who worked there for ages already, showed me, bursting with pride, how I could resize open tabs. But he had no idea how to close them. He just kept resizing them in all directions so he could see the tab he needed. When I explained to him, what the "x" in the upper right corner was for, he was so excited...