It hurt, to know that she'd been replaced to easily. Replaced twice, by Donna and Martha.
She'd thought she was special. She'd thought they were special. Even if there was no them, really.
He'd given up too easily.
She'd never stopped looking for a way to get back to him. And, eventually, she'd found one.
Surely if she could find a way, a Time Lord like the Doctor could have.
But he hadn't even tried. He'd just left her in that parallel universe and moved on with his life. Without her.
Why did you abandon me? She wants to ask.