THE FAVORITE CHILD
There are many sad stories of grandparents and parents who had a favorite child. The "Favorite" ends up spoiled and selfish and the other children are left rejected and wounded.
Yes, your personality may get along better with one child's personality rather than another and so it is easier to spend more time with them and give them more of your favor. But if you want each child to feel loved and favored by you then choose a quality of each that makes them your "favorite".
I like the statement in the book "The Shack" that the God figure says about each one: "I am especially fond of him or her." In God's eyes we are each His favorite child. We should look at our children and grandchildren in the same way. I have two granddaughters who live near me. One is the most like me so she is my "Favorite Mini-Me" the other has qualities that I lack but admire and she never forgets to hug and kiss me goodbye so she is my "Favorite Sweetheart". They both know they are my favorite for different qualities and are proud of it.
"Mini Me" wouldn't want to be called sweetheart. That would be too sticky for her and "Sweetheart" is proud she's different from me. But both delight that they are my favorite granddaughter.
We have to be careful that we are focusing on them and their best interests and not our needs and how they can meet those. I've seen too many parents and grandparents who tried to live their lives and goals through a child and ended up ruining that child's life. In the process their own needs were not met either.
So go ahead have a "Favorite". Have lots of "Favorites". Let each child be free to be the great individual God created them to be and let them know you highly approve and admire them for it. Let each one know you are "especially fond of them."