One thing that struck me as to the difficulty / young-ness of this field is also the fact that it is the only science that is us studying our thinking selves. It's almost like trying to draw a picture of the exact spot you are standing on.
contrast that to something like... geology. i'm sure there was folk geology back in the day about where different types of rocks come from, but for 99% of people they weren't particularly invested in it. so when the scientists came out with empirical research, most people would be fine with it.
but when psychologist confront folk psychology, people often take it as a personal affront. any comment section about psychology research (HN included) is filled with armchair experts contradicting researchers with their own pet theories