There are a lot of myths about being an only child like we get "lonely" and stuff. But really, it does nothing of the sort. It can make us seem a bit spoiled because we don't have to share our room and stuff before school. But that's about it when it comes to the negatives. You get your own room and your own stuff. There's no-one else to push you around/irritate you. You get the full attention of your parents, which is always fun. You don't have to work around someone else's TV schedule, and people don't push you off the computer/console/whatever when you're having fun.
I'd hate to have siblings. I'm happy that my mother upholds a "one child is more than enough" attitude. She says other stuff like "anyone that has been through the horror that is pregnancy and childbirth and then has another child either has memory loss or is an idiot" but I wasn't going to mention that. Too late.

I fully embrace your mother's way of thinking. IF I ever had kids, it would only be one. Because I imagine I could love my own child (as hillaryhwv mentioned), but I'm not fond of other's children...except for my friend's son. I loooove his son. Mostly because I've never met him. The best kind of child is a distant one.