Blue Eyes, Brown Hair
She chooses clients that remind her of him. Blue eyes or brown hair. Sometimes both. It was awhile before she caught onto her own habit, and then she found she didn't care to change it. She didn't know how to change it.
If she couldn't have him, she would have them instead. It was a poor substitute, but it was all she had, lest she confess to Mal that she would love to try something with him, to be with him. She couldn't do that. Not ever. No matter how she felt about him, she couldn't change her own future.
She couldn't change the fact she was dying.
It wouldn't be fair to him.
So, she chooses clients that resemble him - in looks, in personality, in any way possible. She hopes one day it will be enough, that one day it will satisfy her. (She knows it never will.)