To keep you guessing as to which characters will go on the top list let's throw a few more here.

Izumi compared to the other members of the Nadesico crew can be seen as probably the most overlooked character in the series, her appearance shouts goth girl, her voice certainly in the dub makes her sound like the type of person who could tell a good ghost story and her presence is felt through terrible singing, groaner puns and very deadpan humour that makes her laughing very strained as if she's forcing it at times.
In most cases you can write her off as just the strange one and move on, but in a mid season episode that has the crew confront their biggest insecurities, it becomes clear as to why Izumi acts the way she does and even why she's not that interested in the crew's men.
She lost her previous two lovers, one to illness, another to an accident, in the episode she came face to face with the image of one of her dead lovers and you can feel her break character in argubly one of the most tragic moments in the anime.
All her personality quirks are just a coping mechanism which I doubt she has the strength to break and return to normal, something which alot of people can relate to, certainly I can with what the pandemic put me through, if we want to admit it or not.