I don't leave a lot of space - maybe 1 second of room.
Others see that small gap as an opportunity to zoom ahead of me, cut in front of me, and then tailgate the guy ahead of me. They are now one position ahead in the race!
I slow a bit to have a small bit of space again, and another driver sees a gap to move a single car ahead in the never-ending race, once again tailgating the driver in front of them. This happens over and over again.
People need to chill, especially on the road.