Placebos are a ripe topic. Specifically of interest to me, is that it is clear that placebos can work even when you know they are placebos for "solving" things; this implies that they can also work for making things worse.
And letting that sink in is terrifying. Just telling people that they are going to do worse on something can, in fact, cause them to do worse at said thing. Even if the reasons are completely wrong.
Thinking of how this fits in to conspiracy theories and general thoughts on public policy are... less than pleasant, all told. I personally take it as a good reason to have even more patience and empathy for folks; but I don't get that impression from everyone else. :(
And letting that sink in is terrifying. Just telling people that they are going to do worse on something can, in fact, cause them to do worse at said thing. Even if the reasons are completely wrong.
That is, placebos aren't limited to cures.