I can only speak from experience so I would have to say that yes they are all spoiled brats at least until they reach adult hood and find out they have to share.

I was an only lonely growing up, and it was terribly lonely and boring. I always wanted someone to play with me, whether it was house or dolls, or in the backyard or whatever. Because of this I created an attachment to my dolls and stuffed animals naming them, giving them habits and personalities, and using my imagination to create scenarios to enact with them, which also cause me to be very creative. Of course this behavior is normal for the most part, but my attachment continued all the way up until I was around 13 (I know, sad) because I had become so reliable on stuffed animals for companions.

Ironically though, I never really got along well with my own peers but rather with people either older than me as the list states, or people younger than me. In grade 5 my best friend was this girl two grades of ahead of me, and got along great, and always hung out at recces just talking to each other. For some reason though there was this rule at school where younger kids, are not to fraternize with the older ones, she got ratted on, stopped talking to me, and I became friendless again. I still interacted with kids in my own grade, but it just wasn't the same.

I might have been very introverted growing up, but I've learned to socialize more, so I'm not completely closed off and shy when I talk to people. As I got older I appreciated my only child status, after realizing how little households had only one child, and I felt special