I would never dream of thinking of myself as 'bad' granny. I may not do or feel the things that other new grandmothers feel, but, hey, that's me.
My DGS for several years made it clear that DH was the preferred grandparent. Probably beause he has always been the only grandfather, whereas, my companion grandmother lived close by and was seen much more, and as No 2 grandma, seen every month or so rather than every week, in DGS's eyes I was probably surplus to requirement! I knew things would change eventuaally - and they did. My sense of self is not based on how my grandchildren feel about me.
Like Daddima my grandchildren do not dominate my life, and wouldn't even if I had lived next door. I have lots of other interests I want to give time to as well.