I was 8 years into my Megacorp career. I remember a slow panic spread through our Megacorp office as day went on. A TV was set up in a conference room so we could watch the news as things unraveled. There was a lot of gallows humor. One veteran employee joked that at the start of the day, he was planning to send his child to an Ivy League school, but by the end of the day community college was the affordable option.
In those days my main investment was my 401K and you had to call the find out the balance. More than few co-workers checked and wee panicked enough to say they were getting out of equities. But DW and I talked, and she kept reminding me "but, this is not money we need now, right? this is for the future, right? A lot can still happen". Plus, there was under $10K in the 401K. So we made no changes.
I still have my 401K quarterly statement for the 4th quarter of 1987. My equity funds were down 18% for that quarter. While at the time it was not fun, it happened at a good age in my life - experiencing that, and seeing it recover, kept me from panicking when future market downturns occurred, and in fact encouraged to invest more during those times.