Could Rei actually feel emotion, or was it genetically impossible for her?
impossible due to severe autism i'm afraid
She was really confused about what emotions were because she had a giant alien god soul instead of a human soul
By the time she got used to it she exploded though
If you look at the scene where her body is being invaded by the angel she has an aroused expression. Throughout most of the series the only emotion she shows is arousal.
What if Rei was actually a ghost??
too spooky to consider in my opinion
She can feel, but not express.
Rei's problems are largely social. This is why you see Rei smiling naturally at one moment, just to later apologize and ask "what am I supposed to do in this awkward situation?". The answer which was of course, to smile, and she does.
niggah she was cloned given a soul and then thrown into this world without growing up
no fucking wounder she had no emotions at first she had no one to experience them with until shinji came along
But Rei felt plenty of emotion throughout the show, she just has a hard time expressing it properly.
Yes, she could feel emotion, and you see her do it quite a few times in the show.
It's always subdued however, so most inattentive viewers don't latch onto it or Rei in general.
Rei's problem is one of expression.