Right, so shields are extensions of ourselves, they are visualizations that we use to help our brains and bodies cope with input from around us. If a shield is not working against, say a particular person or energy, one has to ask oneself - what is making me susceptible to this particular thing and what about my attitude can I change? The more I think about it, the more I believe that shields are strongly connected to our own knowledge about ourselves and the world around us - and particularly to our own connection and/or relation to it.
For instance, me simply knowing about empathy and energy, changes the way I filter input from the outside - and that is just on an unconscious level. Controlling it is another thing entirely. One can have a seemingly perfect shielding, and suddenly become affected by something or someone, that makes one reel inside.
What I am saying is that a shield is not a magical blanket one puts on, it comes from within - thoughts, ideas, perception, will, and emotion etc. There is clearly a psychological aspect that is deeply personal.
Since shielding is an extension of us, the idea of shielding as a concept that is set apart from ourselves is deceptive, because it hides the real issue, which is our own minds and souls. I guess this is the good news, because since we have free will, we can seek out ourselves, and learn. For some of us that can mean seeking out something that is higher than ourselves - I know that many here turn to God, or something they call God, when they are overwhelmed by this life. Also I think a place like this helps - just to know we are not alone in our struggles, that we can comfort each other.
In essence, shields that come from our own minds naturally don't protect against forces that our minds are not ready for or that are beyond our understanding, consciously and subconsciously. Yes, it's easier to blame the shield than see who you yourself are, but there is no shame in ignorance of oneself, because this world hides us from ourselves. The bible incidentally say that we will one day see the truth as if in a mirror, and I believe that.
And I believe that there is powerful protection against anything out there. I have sometimes felt it as clearly as if something was trying to hit me and instead hitting an impenetrable wall. And I don't credit any of that to my shielding skills, actually none of it. My conscious shielding is, if anything, a product of my own understanding and centeredness, but it doesn't change who I am, or give me magical powers.
Anyway, this is what I have come up with, considering this today.
I hope it can help in some way.
Avic amare a santum