I remember that I turned on the TV while getting ready to visit my wife who was in hospital and was absolutely shocked and horrified at what I saw. The first tower was burning and then I watched as the second plane hit. It didn't seem real and the initial estimates that there could be up to 30,000 people in the buildings (thank God that was not true) made it even more horrific.
It became even more personal when the hospital (in Canada BTW) sent my wife and many other patients home to clear beds for possible injured survivors. Seems the hospital is part of an emergency plan for the eastern part of North America and had to be ready for an overflow of patients.