I like Haruka from RahXephon. She's so bad at hiding her feelings, but fortunately for her Ayato's so dense he doesn't notice how bad she is at it. She carries around so much of a burden for so long, I think she qualifies as one of the most legitimately pained people in any series ever....

Sure, losing a loved one hurts. But getting them back and still not having them, but having them dangling right in front of you like that? Yeah ...