Shock horror deep pain for the victims as their plight unfolded, mesmerized, couldn't take my eyes off the telly.
Then became fascinated with the crime itself how it happened, the logisics, jet fuel, steel melting, freefalling buildings etc etc and have remained intrigued by it ever since.
I think the arnchair forensic research stuff was my way of coping with the unthinkable that if it could happen in the middle of NY it could happen anywhere.