Have you ever seen a dog standing at a glass door, waiting for their owner to open it and let them through, yet not realising that it is already open? They’ve been trained not only to wait for permission but that there is a barrier between them and the outside world that they cannot pass through. Over time, they will accept the barrier exists even if the door is open and there is no real physical limitation.
We do the same thing with mental barriers we place on ourselves or we believe others have placed on us.
Div Prakash 