I was bored quite often, but I never considered having siblings, as a child. I just accepted the status quo as children often do.
In my early twneties I remember a realisation that my best friend despite how close we were, would never be as close to me as she were to her very-close-in-age sister, which was a pivotal moment.
I do not dislike being an only now, it just is what it is. It has its merits, I am comfortable in my own company and I am empathic but also a little confused initially when I hear of women not wanting to go anywhere by themsleves, not daring to walk into a pub/cafe alone etc-some of this is my being a feminist, but some of it is likely due to me always having been alone.
The main drawback I think, I am not sure, for me as a child was my Dad's weird obsession with me as a project. Perhaps having siblings would've made this worse? Perhaps it would have been better. He wanted a boy. And he tried to make me into something that I just weren't, and he was abusive. I wonder now sometimes what things would've been like for him if I hadn't have been an only. Would he have laid off me a little? Perhaps not. If he had a boy as well, would he have ignored me in favour of him? That would've been preferable-even now, with me in my 40s and him in his 70s, he resents me for not being what he wants and my Mum for being a loving parent who I 'sided' with (that is, favoured because she was actually nice to me).
What if I had have had a sister?
It's a double-edged sword as an adult. My low self-worth issues (mainly if not 100%) caused by my Dad, means I am an underachiever despite being more than quite intelligent, but I will benefit from 100% of the inheritance. I also dread being left as his sole carer if anything happens to my Mum who is significantly older.
I have two maternal first cousins, both live in Texas, youngest 6 years older. Seldom saw them as a child and that is a significant age-gap regardless, we'd have never been close and I haven't seen them since I were 10 and under.
Dad is also an only. I have a half-Sister from my Mum's first marriage, significantly older who had already left home when I were born. We're not close although we get along fine and I were away at Uni and then living in a different city when her children were growing up, so although I love her and her family, we're not close.
Just me really.