I found this in underworldwiki
"She grew up practically alone in a very cold world, raised by a woman that had seen the worst of the worst. Her childhood wasn't pleasant. When they were trapped in the Fade's Nightmare, she was confronted with a spirit impersonating her mother. Morrigan wasn't fooled by this though, in fact the only thing she said the Fade Spirit got right was having her “mother” slap her. This indicates that she grew up in harsh and abusive environment. While the environment was excellent for developing her survival instincts and sharp wit, it was detrimental to her emotional development. Morrigan has no idea how to act in public or how to interact with other people. She doesn't understand the outside world, she admits that she knows nothing of the customs most humans take for granted such as knowing when to look someone in the eye, or when to shake someone's hand. All of these things are things that she never had to learn living in the wild, and when she's thrown into the outside world it's a bit overwhelming for her.
It wasn't just the outside world that Morrigan finds overwhelming though, she's also a fish out of water when it comes to interacting with other people. When the Warden presents her with the gift of a Gold Mirror she has no idea how to react. She's never gotten a gift before that didn't come with strings attached and at first she's convinced you must want something in return. When she finally accepts that it's just a gift, she actually admits she doesn't know what to say. She has no social skills and has no skill for actually making, and keeping, friends. Yet, at the same time, she desperately wants them. Deep down underneath her ****** exterior Morrigan is actually a very vulnerable and broken individual.
The first time Morrigan speaks of the mirror she stole, she states that sometimes she wonders what might have happened to that little girl with the mirror. Another time she states that she envies you for being able to say that you loved your mother. These are things that she wishes she could have but they're also things that she knows she never will have. She's built up exceptionally thick walls to protect herself from the hardships of the world. Her prickly exterior protects a very soft interior, which she'd do anything to keep secret and away from harm. Friendship is one of the few things she actually fears.
When you actually reach friendship with her, she makes a statement that proves just how much she wants friendship and craves companionship. She tells the Warden that she knows she may not deserve their friendship, but that she greatly values it. This is after she actually admits how terrible she is with people. At that moment she almost starts to cry, and so she quickly pushes you away. That's her answer to getting close to someone, she pulls away. She's terrified of close relationships because they invite feelings into her that she's never had before, feelings she doesn't understand. All of her life she was taught that love and friendship were things to be avoided, and now she has no idea how to handle them. The only thing she knows how to do is flee, and that's exactly what she does."
It fits her well.