Had this happen once. I arrived without an appointment about an hour before the office closed. They allowed me in and took me into an exam room to wait for the doctor. After nearly an hour, I went to look and see what was happening. The staff were in the process of closing up for the day. They had literally forgotten I was in there.
Had the exact same thing happen, except it was that someone else with an appointment had my same name. So the schedule got messed up and thought we were the same person. I stuck my head out 45 minutes into sitting in the room, and they were very confused. I then waited another 45 minutes cause they are chronically behind. I don’t go to that doctor anymore.