Does it Matter if the Placebo Works?

I am reading Give and Take by Adam Grant while taking in the bright sunshine and sea breeze in Oceanside< California. Goodreads, description reads;
For generations, we have focused on the individual drivers of success: passion, hard work, talent, and luck. But today, success is increasingly dependent on how we interact with others. It turns out that at work, most people operate as either takers, matchers, or givers. Whereas takers strive to get as much as possible from others and matchers aim to trade evenly, givers are the rare breed of people who contribute to others without expecting anything in return.
I was taken by a line on page , that I read a few days ago and continue to ponder. “Teachers’ beliefs created self-fulfilling prophecies.” Grant is speaking about some remarkable professors, in particular CJ Skender and his approach to judging capability and Skender’s remarkable record of teaching, influencing and encouraging 100’s of medal winning students that have gone on to lead successful ventures. It reminded me of Henry Ford’s “Whether you think you can, or you think you can't–you're right.” that I think applies to those we are supporting, nurturing, encouraging, teaching, loving as well.
It got me pondering – who am I under valuing, under encouraging, under challenging in my life. I espouse regularly Thomas Jefferson’s assertion that “given the opportunity and circumstances, every American will take care of himself, his family, and his community”. I have used this in speeches, debates, writing many times and follow it with “ I believe everyone is more capable than they are given credit for”. Do I live out that prophecy? I think I do with my grandchildren, all children really and I feel like that was my approach with my kids, their friends, and students in my life. Do I still act on that belief? Are there important relationships where my assessment undermines people that I get to work alongside?
Are there people you love, you work with, you care for that you believe has limited capacity or ability? Are you creating a self-fulfilling prophecy for them? What would happen if you set higher expectations for them (yourself) and demonstrated that you believe they could be exceeded? Are you willing to raise the bar, with encouragement and confidence for the next month? January only has 11 days left, would you extend the power of positive beliefs to yourself and others for the rest of the month? I am going to give it a try and record my observations. I would be interested in what you discover. Please let us in on your findings, either here in comments or through email below.