Gym “Buddies”

Do you have gym buddies? I am not talking about the person you go to the gym with, I am talking about people you always see in the gym. There are always on the same treadmill. You say hi to them, but you do not know their name. If they are late to the gym and someone goes to their treadmill, you feel like telling that person, that treadmill is taken. Today I went to the gym and one of my gym buddies was not there. I could not help but wondering what had happened to them. I hope the gym buddy is okay.