What makes a head worth keeping?

Looking at all the heads I've done (a total of 7 so far) I think some ppl must wonder how I am able to just let them go and whether or not I have any attachment to them. The truth is that I put a lot of myself into anything that I make and this is the first time I have ever had to let anything go that isn't easily reproducible. If people have taken time to read the little blurbs I have written about each head, they can see that even if they don't have specific stories, each head is unique and each is a different character. If I could keep them all I would but I am not someone who is very interested in making photo stories or dioramas so I wouldn't really do much with them except keep them safe in a box (which is where the ones that haven't sold yet are right now). I know that if I sell them, they will go to someone who will probably put them to more use than I will. Another thing that makes it easier to let them go is that I did create them with the express purpose of selling them. For me the enjoyment of dolls has more to do with the creation process than anything else that comes after. I am also interested in seeing how the new owners decide to develop a doll I've painted. They would probably see different characteristics in the head than I do and it's fun to see how a character develops.

EDIT: There is one head that I am keeping and will never be selling. That head is my first. (Milla is technically my second head but she was the first I painted to sell.) She was never finished which is why I don't have photos of her here but in due time.

So after that long explanation, let me introduce you to two new heads. Song and Llewyn.

Song is an East Asian beauty. At first glance I assumed she was quiet and sweet. Her character seemed a little flat but I thought she was pretty so I left her alone. The next day I looked at her again and realized she looked like she was laughing about something and that she had a bit of an attitude about her. She's the kind of girl who let's you think that they are simple and easy to understand when they are really laughing at you silently.

This is Llewyn. She's...something else. We don't get along and I have to say she is the first doll head I've painted that I've been so frustrated with. I like her but I spent hours trying to fix some mistakes I made on her (and she feels nothing but disdain for me because of this). Also she seems a bit too preoccupied with the shoulds and should nots for my taste. She'll probably grow out of it but for now she's got a stick up her butt.