I have to process the questions with my parents because I've got a few and I don't even think I can post them here.
But, to my deceased grandparents, all of whom I never got to meet:
"Were you really as cool as my parents tell me you were? Would you spoil me like every other kid's grandparents? Would you have filled up a hole in my heart that I'm not really sure is there or not? And most importantly: What were you like?"