It is only a subjective, i.e. my experience, but it gave me the "knnowledge" that acupuncture is not a placebo. Due to a harsh reaction to a certain kind of medicine my nervous system was harmed by iatrogenic damage years ago. When I was in a better patch of this horrendous experience, I had two sessions of acupuncture, because having had good sessions before (long before I had the reaction), I thought I could increase my wellbeing and help my system to heal. That was a dead wrong conclusion as I felt much worse after the first session. I did not attribute the worsening to the acupuncture, though, and had the second session a few days after the first one. After this session, I felt worse than ever before and had terrible symptoms abound.
In my eyes, this is only explainable by a real effect of the acupuncture. Could not have been a placebo effect as it was negative, and no nocebo effect as I had no negative feelings towards the sessions due to my positive experiences before. I didn't even connect my worsened symptoms to the acupuncture before the 2nd session.