Control theory is an actual, real engineering subject. Not only this self-help, psychology, wow, mind-blown, feel-good BS.

Yep! That's one of the reasons I find the application of controls to psychology as interesting as I do. I've taken about two years of controls classes at the graduate level, with a heavy emphasis on their use in aerospace (as my examples might suggest), though I don't yet use it in my professional work (which is more pointed towards numerical optimization and machine learning).