As I've said on another thread, the tightrope that many grandparents have to walk is like the finest silk thread.
You have to love your grandchildren, but not too much
Care about them, but not so much that you actually ask to see anything of them.
Be available when needed, but otherwise be invisible
Never have an opinion (or anything that sounds it might be one).
Never have a feeling or preference of your own (while accepting every preference that your child and their spouse might have)...
...I could go on forever.
I'm so lucky in my daughter and son in law, who see me as a person in my own right. Who don't impose anything on me, who appreciate everything I do for them, who love the relationship that their children have with me as much as I do, and who respect my own feelings and that I also have a life and personality of my own.
I really do feel for the mums and MILs of some of the people on this thread. They clearly can't do right for doing wrong, and have to just sit on the shelf until required.