I remember walking through the streets of downtown Chicago as most of it (outside newsrooms, obviously) was going home early. The eeriest thing was hearing conversations all about the same thing. No laughing, no joy, nothing but hushed tones. My wife and I took our two toddlers to the park for a little escape. That didn't really happen, because it was too quiet. We live near Midway Airport, so it was unsettling that we DIDN'T hear or see any planes going overhead.
I remember the feeling of, is it ever going to be OK again? The next day, going to work, WXRT is playing America-themed and otherwise appropriate songs -- later, I would do a profile of a rock band from Israel in which the drummer said the same thing happens there whenever there is an attack. I remember bursting into tears at the wheel, at the corner of 103rd and Western, when U2's "Stuck in a Moment You Can't Get Of" comes on. At one time, it seems to describe the situation perfectly, and serve as a reminder that eventually things get better.
I remember when, at least in Chicago, normalcy began to return -- Mike Brown's first (of what what would be two) game-winning interception TD scored off a deflection in OT. At the train station, people are talking excitedly about the Bears game. 9-11 isn't a reminder of what's important, but those conversations are -- the importance of having the luxury of talking about unimportant ****.
I worked in Tower Two from 1994-96. For a while, years afterward, I had dreams or thought where I could vividly see myself getting off my A-C subway stop at Chambers Street, walking up Church Street, stopping to get a coffee, donut and paper from street vendors near the WTC plaza, and then walking across to my buiding. I even had visions of the mall underneath. It's like how you visualize someone who died as living and breathing in front of you.
On a lighter note, we'll also always remember 9-11-01 as the first day my then-two-year-old daughter climbed out of the crib on her own. My mother-in-law was watching our kids that morning, and as she was viewing the coverage (my daughter has always been a late sleeper) she heard a loud THUMP from upstairs. Given the circumstances, she thought a bomb went off. She was relieved to see it was just her granddaughter, proud of herself for her newfound climbing skills.