Having a favorite child?

So I was having a conversation about having multiple children and favoritism came up. Of all the families I know, there’s usually a favorite child. Not saying the other child/children are treated poorly, just that there’s an evident favorite. Each parent may have their own in some cases both parents have the same favorite in others. So I’m wondering, do y’all think it’s inevitable to have a favorite child when you have multiple children? Is it something a person should be ashamed of if they do?