I am an only child and Brunie was the sibling I never had. I begged my parents for a brother or sister for years, to no avail.
Since Daddy was a Marine, we moved frequently. I had three different first grade teachers and was always the "new girl" at school. The average "military brat" attends 10 schools in 12 years - some move as many as 36 times. They have no "hometowns" to go back to and rarely know their extended families.
One of the positive effects of this lifestyle is "brats" learn to get along with anybody, from anywhere. They can move and take risks. They're not afraid of change. At the same time, some brats become "change junkies" and can't settle down. Others have difficulties with intimacy, and lack a consistent sense of self.
Although all the other kids I knew were also Marine brats, dealing with the same issues I was, they all had brothers and sisters, which to me seemed like "friends who lived and moved with you". I experienced a great deal of loneliness as a child.
Mother and Daddy bought Brunie for me when I was in the fourth grade. She instantly became my best friend. Whenever we moved, Brunie was always there for me, filling in the lonely periods of adjusting to new towns, houses, teachers, and friends. She was my first dog, my playmate as a child, and my loyal friend for the 15 years of her life.