there are two kinds of grandparents: tired or lonely. Most of the time, we are lonely - lonely grandparents, at least. All of our children live 3 hours or more away from us, so it is a very special time for us when they come to visit.
We aren't lonely right now. But we ARE tired. A good kind of tired.
I suspect it is the same with ALL friendship and relationships. Without them we are lonely. But relationships and friendships take time and energy. Relationships can leave us tired sometimes. A good kind of tired.