I was sat at Macclesfield bus station, listening to the radio while waiting for a bus over to Buxton. Scheduled broadcasts were interrupted. I listened for a while, a little stunned, then mentioned it to the little old lady sat beside me.
She said it sounded upsetting... then told me she was pleased because she'd just bought some slippers, the final Christmas present on her list.
At the time I thought this was a strange reaction, even for someone who probably grew up in WW2. But I often wonder if the whole world should have reacted like that. Terrible tragedy, but life goes on. We seem to have spent much of the last decade proving that Bin Laden was at least partially right about the West's attitudes and lifestyles. Morally confusing wars, self inflicted debt crisis, people rioting for trainers and mobile phones... strange times.
That's not to say I approve in any way of what happened, obviously, and it is hard to imagine the kind of fear felt by those trapped in the Towers and stay sane. I never forget that, and whenever I'm in a restricted environment, like a multi-storey building or tube tunnel, I always try to have an escape plan.
Chances are I'll never need it; big fires or disasters are very rare. But 9/11 was a very significant reminder that every bad day starts out as a perfectly normal day.