My mother's parents and my father's mother studied back in the '50s.
My mother's parents were relatively well off financially, so I don't know what emotional motivation caused them to become Witnesses. My mother really took to it and made it "her own" so to speak. She pioneered and moved to South Carolina to help out where the need was greater, and there she met my father.
My father's mother faced severe problems trying to raise a family without much help from my grandfather. If my father ever wrote the story, I'm sure it would make for an interesting read. From what I understand, studying with the Witnesses saved my grandmother's life because she was at the end of her ability to cope. Being a Witness gave her something to live for, and she made great efforts to attend meetings and go out in service despite severe opposition from my grandfather. This probably had a great impact on my father.
My parents are still faithful and active, and I expect they will be in for life. I do not have any bad feelings towards them for having raised me in this religion. I don't believe there is any such a thing as a perfect life, so I try not to piss and moan about "what could have been."