Before I understood this lesson, my life was, to be blunt, a wreck. I did not have good boundaries of my own, nor did I maintain them. Even worse, I had little concept of the boundaries of others. Even as I started learning about boundaries, I still found myself crossing them quite frequently. True, sometimes I did so not out of malice, but simple unawareness. And yet, even when done in ignorance, I saw the grievous harm that could still be done. Even then, it still took many times of being on both sides of the boundary violations for me to "get it" on a primal level.
Boundaries matter. They matter in ways few other things do.