I have an older sister, and I can't say that it have made my life better. She always had some serious agression issues when she was groing up. She treated me like crap, and she was always fighting with my mother, whom I deeply respect. I really hate her persona. She have no respect for other humans, and she's so ****ing spoiled. She may be my sister, but that's just a title to me. There's no love between us. She's in a wheelchair now. She broke her spine last year, so she's paralyzed from the waist and down. It's a cruel fate that I wouldn't wish upon anyone, but I don't feel sorry for her. I know that's a bad thing to say, but it's the truth. I just hope that in time, she will learn to respect others, and thank my mother for all the hard work she had to endure thanks to her, all her years.
Another thing about having a sibling, there's always a sense of competition between you. At least that's what I've always felt between me and my sister. Even though she's 5 years older than me. But I can imagine that there's a lot more pressure on you if you're the only child.
I get really jealous of siblings who have this really strong bond between them. It looks like so much more than love. Lucky them!