I honestly do not believe it's to do with perceived attractiveness. How do you know that all those people getting hugs didn't ask for one? Maybe your therapist waits to be asked for a hug. Maybe the people you have seen hugging just have a really good rapport with her and are open to touch, maybe she thinks you don't want that, maybe you give off that vibe that it would not be welcomed.... there's a million reasons why she hasn't hugged you and the very last one i believe would be to do with your looks.