The reason many are rightfully skeptical about its status is found in the body of scientific knowledge—psychology has failed to produce a cumulative body of knowledge that has a clear conceptual core that is consensually agreed upon by mainstream psychological experts. 

Psychology Today. "The “Is Psychology a Science?” Debate." Psychology Today. n.d. Web. 28 Oct. 2019. <https://www.psychologytoday.com/blog/theory-knowledge/201601/the-is-psychology-science-debate>

I think that's a very concise way of stating it. Where is psychology's core theories that everything else in psychology is based on? Where is its laws of thermodynamics? What major theories that are testable, falsifiable, and rigorously tested does it have? 

Psychology is a field of study, it is a discipline, but it is not a science.

Doing experiments doesn't make a field a science. Applying statistics to data doesn't make a field a science either. 

I think many people have accepted the idea that psychology is a science just like chemistry, physics, and biology, but I think that idea is unsubstantiated. Psychology's success comes mostly from the field's efforts in promoting it as a science rather than it's own merit as a science.