The Nine Centers in Human Design represent energy sources that are either running all the time and providing a consistency you can count on, or available sporadically, directly helping you only some of the time but also acting as a resource to those around you.
So, you can tell what you’re going to do in certain areas or what you might be able to do in others. But the “might” areas are a way for you to be useful to other people.
Everything is energy. These Centers and their energies also interact with the Centers in other people.
If you know how you’ll act, you can plan accordingly. That’s your Defined Centers.
If you’re not sure how you’ll act with one Center, that’s the one that people can influence in ways you don’t want. So you stay aware that you have an exposed flank in that area, and act accordingly.
Either way, you just have to be aware. Hence, the “no good or bad” setting of your Centers. They just show you how you are.
As with all that’s been revealed to me in my Chart up til now, the knowledge of my Centers has blown me away.