(A day late because I am an easily distracted doof. Also, minor spoilers regarding the direction of Eva’s character in the series.)
When I first watched Monster, my reaction upon seeing Eva drinking herself into oblivion and pummeling herself with memories of how she screwed up with Dr. Tenma was probably similar to many people’s — “She is getting what she deserves!” Now, though, I cannot help but be horribly sad watching Eva waste away while Inspector Lunge tries to pry information from her.
It would be easy to say that Eva is bitter, and really, that is the image she wants to project to the world at this point in time. She is the tough, bitter woman who unashamedly runs men through the wringer to support her own lifestyle. Eva wants to be hated, despised, by other people because being the object of another person’s hatred may be able to make her briefly forget being the object of what she assumes is Tenma’s scorn. The alcohol helps with that, too — nothing hammers away the memories like a slowly disappearing bottle of whiskey, after all.