What I really mean is that usually, my characters just sort of appear in my head fully-formed. Or at least, almost fully-formed. They often come without names, their personalities are intact and so are their physical features, I just have to slap a name on them. Really, that's the only decision I make about the characters, (and it's a hideously difficult process). Occasionally, I'll tweak ages, but that's pretty much it. They just spring into being, like meeting a new person in real life. You don't chose how old they are or what they look like or how they behave, they're just there. And for me, that's what my characters are like.
Right now, however, I'm working on creating a character. I realised my main character (who was pretty much cooked but went through several names before I was happy) needed a friend. This friend did not occur naturally, I had to build her. I had to decide gender, height, build, hair colour, likes, dislikes, annoying habits, wardrobe, hobbies, family...everything. And I've really enjoyed doing it. I think I always felt a bit sorry for people whose characters didn't just come naturally, (I'm a horribly smug person, I know), and had to work on that bit too. But now, I kind of wish I'd had to do this sooner, because designing people is really fun.
Naming her was still a complete pain, though.