Hopefully, you did not leave a sock at the starting line?
Down at the track for my pace workout this morning, I saw one sock near the starting line and another about 20 yards away. I guess it was warm and they decided to remove them.
Socks are good to absorb sweat and reduce friction which can create blisters. Yes, there are arguments for running barefoot too but that doesn't work very well in an urban environment.
Bottom line: be prepared for your workout. Make it a good one!