My biological Grand father on my Mum's side. I never knew him at all, and would have liked to have known more about him and what he knew and thought of us, if anything. Also, to get a picture.
My Grandfather on my Dad's side - He sounded like an interesting chap, but he died before I was born...... And also, his brother, my Uncle Hugh who was killed in a Wellington Bomber over Berlin in 1940(ish). I would like to have got to know him and at least get a picture of him - We have one picture of him, but it isn't very good, and he's being shaved by his brother, my Grandpa at the time.
I would find it hard to tell him not to join the RAF!