My grandmother was my main carer and I bonded strongly with her. My mother was more like a sister, very young she was always at work or out dancing or out with friends. She did a lot with me though at weekends and I loved spending time with her. I felt special. [Until my step father came along when I was 10...long story]. From then on our relationship was fraught and difficult.
My grandmother felt more like a Mum to me throughout, and when she died 36 years ago I was bereft. I miss her so much even now, we did have some giggles, did so much together and she was an enormous influence on me. When I am in trouble I think of her, ask for her help. I think of her most days anyway.
When my mother died we had become closer and I was so sad when she died 12 years ago now. I loved the lovely side of her, our early years [not the carping critical, judgmental side]....I long to hear her voice again on the phone 'Hello, it's only me...' She had a tough time of it in many ways, but I always knew deep down she was on my side and would always listen to me. She didn't know how to show/give affection in any other way.
So I guess I was lucky, I feel I had 2 mums. Love them both, still.