Sister is probably the most competitive relationship Posted on March 6, 2017March 6, 2012 by admin “Sister is probably the most competitive relationship within the family, but once the sisters are grown, it becomes the strongest relationship.” — Margaret Mead Author: Margaret Mead Category: family Tags: family, Margaret Mead Spread the love Related posts: The joke in our family is that Together, we can help make sure that Percussion is the most adaptable family of Nobody actually played tennis in my family.