Siblings working together

I have watched my mother's and father's siblings work together recently. In the past year, both my grandmothers passed away leaving the division of their things up to their children.
My mother's mother decided that she would give everything away before she passed away, so there would be no fights amongst her children when she died. My mother and her sibling quietly sorted and distributed the remaining items my grandmother had. No fights or hard feelings.
My father and his sibling recently gathered together to divide everything. My dad's parents were world travelers back in the 1950's and 1960's and had collected some priceless items. My aunts organized all the items into categories. Then, each sibling randomly selected the categories they were picking first in. No arguing, squabbling, or complaining. Everyone was able to work together and no feeling are hurt.
Normally, when I have talked with those that have had to divide up their parent's items between siblings, it seems that causes fights, hard feelings, and resentment. It has sadden me to think that after a celebration of someones life is destroyed because of things and emotions masked by sadness.