Friendship Amongst Enemies: Summer of My German Soldier

Why is "friendship amongst enemies", a major clue in Summer of My German Soldier? I know what friendship amongst enemies feels like, and it is important because it is the reason why we continue to have 'enemies' and challenges in life. Patty was living her life like she was a teenager in a high school, and no one wanted to be her friend because she was different from all the other kids.
<Tab/>Our enemies often become very helpful to our lives by making us better and opening up our minds and hearts to become stronger. For example, when Ruth said to Patty on page 114 - "Like th…