Where and when were your grandparents born? (both sets) What do/did they look like? What were their occupations? How did they come to meet and marry?
This is a important question, because this moves us on to the next generation. Family members did not always come from where you thought they did. My fathers family was in Ohio when he was born, but they were regionally from Michigan. My mom was born in Michigan, but her family was originally from Ohio. Both families moved a great deal prior to getting settled in one place, but would eventually locate where other family members had already located.
Asking questions about appearance may not seem like much, but they may provide clues on ethnic origins. It will explain many of the features and characteristics of our current generation that we may not understand today.
Jobs were so important to understanding our nations transition from a Agrarian society to a urban setting. In my own family they had been farmers for generations, but then in the early 1900's they moved to cities and started working factory and railroad jobs. They moved from living on large pieces of land. They located in apartments and city houses. Many things had changed from living a farmers life.
It is important to understand where your grandparents met, because it will offer clues on other family members. Did they meet at church or school? Maybe a place they worked or someone that lived in the neighborhood. Were they friends with other family members? All of these are important facts for our continued genealogical journey.