What is the reason to want to be part of an social memory complex?

[Diana]

Maybe upon discovering that 'hiding thoughts and experiences from others' is actually an illusion?
Or upon discovering that there are 'others' who can easily access his/her thoughts and experiences?

Yes, like A. Cube being able to see inside everything in A. Square's world (Flatland).

I think the real underlying issue is processing catalyst. Often the things one hides are the result of unprocessed catalyst. Some of this is hidden even from ourselves—which is a function of our brain's response to trauma.

It seems to me in one way or another, it boils down to acceptance. But acceptance is not "giving up," "giving in," or being a victim of the world. I think, at least for me, acceptance involves courage, and a certain strength of self, a commitment to one's core integrity and path. Little by little we learn about ourselves and the environments we are in. A key feature of acceptance might be forgiving ourselves, and this is the hardest thing. Being under a veil, being brought up by parents or caregivers also under a veil, sets the stage for ignorant (in the sense of being unaware) actions which can haunt one later on (regrets, etc.). 

There is very little guidance in this world on processing catalyst. We are fortunate to have the Ra material.