I remember that morning, and the days after. The shock of it all. If you will forgive me the TL;DR:
I was living in an apartment in Chicago's South Loop. I was working for a phone / cable TV / Internet company; they had facilities in the same building (which was sort of several buildings that connected to one another). I was working from home that morning so I could let some contractors into the facility, and be there while they worked. I had 'always on' Internet since I was in the same building as our network. I rolled out of bed, plopped down in front of my computer and saw the chatter on our company's internal chat... what was going on? I turned on the TV....
It was a huge and terrible thing. I remember feeling like we had fucked up so bad to let this happen. I felt... I felt like I should have zero tolerance for the kind of medieval thinking that led to this action. I felt like this was revenge for the Gulf War of the early '90s. I didn't know, I just felt. I felt I should be doing more to protect my fellow citizens, with whatever skills I had. Whatever moment of clarity I thought I had, it passed.
In the days that followed, I was pleasantly surprised that my fellow Americans largely rallied behind our country and didn't just say we deserved it. I always remember... there was this small flower shop I happened to walk past every day on my way to or from work. I always looked in because, frankly, there were always cute girls working there. On 9/12, they had drawn an American flag on the chalkboard in front of their store, and were giving away small American flags. That was the first time I saw the pro American sentiment after 9/11 and it lifted my spirits.
In the years since I have felt like 9/11 was the result of a conflict between two entities, the United States / the House of Said and Bin Laden / Al Qaeda that wanted to influence Saudi Arabia and the Middle East in general. I have no problem condemning 9/11 however, period, full stop.