This is a case that involves a red cell transfusion; I know it doesn't involve fractions but it happened before the change in doctrine.
My disfellowshipped grandmother almost died because of a low blood count after surgery. My mom tried to fight, tooth and nail, not to let them give her the red cells she desperately needed, her reasoning was no one should be given any blood at any time. To make a long story short, my grandmother decided to take blood and the relationship between my witless family and my grandmother (and step-grandfather) was never the same.
My grandmother lived for about five years after this incident; she was grateful for the "medicine" that saved her life and I was equally grateful to have my grandma for that "extra" time.
However, since my step-grandpa was the one pushing for the transfusion and ultimately the deciding factor, my family treated him like garbage from then on.
So, yes I have “evidence” it affects peoples lives.