My DD is 8.5 and she is an only child. She is, I swear it, pure joy (bear in mind that it is almost midnight and she is fast asleep so I have my blinkers on! lol). She is not only my child but also a little sister and my lover.
We actually call each other lovers and always have lovers time daily, even if it is just a cuddle on the sofa. On the w/e we are either out seeing plays, eating out or hibernating indoors listening to music and just being silly.
It is not always perfect mind but we are so intune with each other's moods and peculiarities that even when things are shaky, the dark cloud never lasts. I think if there was a sibling, it would be too easy to stay mad for longer with her because you would divert attention to another child to punish the naught child even more as if to say 'you could be the one getting all this love if you acted like this' but with an only child, you have none of that powerplay to hide behind. No point scoring going on.
Ever since DD was little we have always gone on random trips together and there is something about just having the one child that makes it possible to book holidays to far-away places without a second thought.
We are off to South East Asia in August for 3wks and last year we were in West Africa for the same period of time. We have adventures together and have no one else to worry about.
With one child, you can also truly invest in getting to know them and their dreams. And assisting in making these happen. I have all the time for my child when I am not working and I am not tired out from having to split this with other children.
Only children are also very easy in adult company and this makes them a pleasure to converse with. You also don't dumb down conversations within the home when you just have the one, I think this would be too easy to do with 2 or more kids running the roost. Without having to play mediator between quarrelling siblings, we can talk about things going on; for her, for me and all around us.
It's hard enough thinking you are not doing all you need to for your child and with one child, I seriously feel that this particular guilt is lessened!