I have been going to the same gym, a large one, for 18 months. I go the same three days of the week at the same time. There are three people I know from other venues who I see there once in a while. However, there are some I see regularly who I do not know. When I am on the treadmill, I look around (not plugged in, am I) and I take attendance. I notice the same few people on treadmills, one on a bike, and another who is always stretching on the mats. Others I note moving from one location to another.
I wonder if they do the same?