"As sad as this may sound, often the hardest people to get along with are our own family memebers. Think of the inter-familial relationships we see in the Bible: Cain and Abel, Jacob and Esau, Joseph and his brothers, David's sons... even if most of us haven't sold any little brothers into slavery in Egypt yet, it's clear that getting along all the time is something all siblings struggle with.
Behold, how good and pleasant it is for brothers to dwell together in unity! Pslam 133:1
It is likely that if we can learn to get along with our brothers and sisters, we can get along with anyone. Family life is where we practice Christian love and character.
Every time we are annoyed or provoked, God is testing us. We should learn to think of each trial as a moral test, which reveals where we really srand in our Christian walk. Do we pass our moral tests and refrain from exploding at our little brothers, or do we fail? These moral tests are an opportunity to mature in our godliness. We should be thankful for each one and make the most of it (James 1:2-4)"
Taken from So Much More by Anna Sofia and Elizabeth Botkin~Chapter 13-pgs. 199-200