I knew my father's mother and my mother's father, but they both died before I started researching the family.
Looking back, I realise that my paternal grandmother never spoke about any of her family other than her two brothers, both of whom I remember quite well, and their families. That was in spite of several of her cousins and their descendants still being alive and living in the same town!
She also tore out of the family albums any photographs with herself in them.