"All concepts are fantasy and shouldn't be mistaken for reality"
The human mind loves concepts – because these are the products of its favorite activity: to conceive – form a mental representation of something. These representations are handy to say the least. Without concepts of things to "hold in mind" long enough to compare with what we experience, we'd have no basis for understanding. Collect enough concepts of things, and we're able to develop wondrous conceptual creations like an identity, world view, or beliefs and theories about stuff. And as our concepts become more refined and true to life, our ignorance abates and understanding deepens.
However, when our mind becomes too enamored with its conceptualizing powers, autocentrism sets in. Favoring its holographic account of things, the mind conflates its beguiling world of concepts with the real world, and can't be bothered to sort it all out.
This is where all our troubles begin. The problem is that concepts aren't the things they represent, they're only mental activity about the things. So to mistake concepts for reality, to hold something in mind counting on it to be real, is a risky game where getting it wrong is subject to very real penalties: namely conflict and suffering. If we are privileged with a mind whose purpose is to understand reality, it's our responsibility to get it right – and reality, suffering and all, is here to help.
On the other hand, holding our concepts of the world loosely in mind as we study the real context of things, favoring actuality over conceptualization as per ontocentrism, our chances of getting things right are much more realistic and less prone to adversity.