I think an individuals personality is determined by two factors, your genetic makeup, and your environment.
I think the genes are stronger than the envirionment, hence we see people that are much nicer personalities than they should be, in theory, when you look at the influences on them during their life.
I think my oldest sister may have the cult personality as her "genuine" one, I have not seen any evidence to the contrary, my other sister, though over sixty years in, and full time pio. for over forty years, not so much.
Me, I don't think I inherited any thing much religious gene wise, I just inherited the "Awkward gene", hence I never took on the cult personality.
My, B.I. Law ( oldest sis's husband ) said as much, as a kind of insult, that I had never been a 100% JW, I said "You are right, thank you !" he looked puzzled that I took it as a compliment.
I think most J.W's have a genuine personality, buried and hidden, at least whilst they are around other JW's, it is just waiting to be released though.
Edited to add, I seem to have repeated my previous post, on page one, which I had forgotten about (silly old bugger ain't I?) but it does underline what a right royal pain in the ass my Culty Uber-Dub oldest sister is.