On my mom's side, my grandparents both passed away from cancer: my grandmother when my mom was 16 and my grandfather when I was 5, so I have no memories of them. My grandfather on my dad's side passed away when he was young and my grandmother developed Alzheimers when I was 6 and it was a very rapid progression, and she lived with my aunt so I never really saw her.
But I was very close to my great grandmother until I she passed away when I was 8 and my fondest memory of her was when I was waiting in the car with her and I asked if she would be at my wedding. She said, "You won't see me but I'll be there with you, that day and every other day." Shortly after she passed away, but I'll always remember that and I have her wedding ring so she'll be a big part of my wedding day.
I was also close to my great aunt (who passed away when I was 17) and I can remember cooking with her a lot. She had always lived alone, never married or had children, so she was kind of perfectionist and there are certain things I now do where my mom says, "I never did that! Why are you like that?" For instance, my linen closet is perfectly folded and organized like a department store. So far I don't iron my sheets before I put them on my bed, but I guess that could come with age... My boyfriend always makes fun of me because even though my great aunt helped to raise me, when she passed away I didn't get anything from her so I took this hideous green vinyl step stool chair she had in her kitchen that no one else wanted and was in my parents basement even by the time I got my own place. Since that was where I always sat, I sat it in the same place in my kitchen.