Good point, but your parents will never say to you "we need to drop certain functionality to improve the core framework in order to secure a stable release" or "private static long MAGIC_NUMBER = 1024*1024; ?!?! you crazy man!! what the hell does this do?"

I personally find it easier to work on a project when I have somebody to look things over with. It's very easy to get side tracked when you work on things by yourself, well thats what I find for myself any way.