Ok, I admit to being a bit of a Trekkie. My favorite is Star Trek Voyager, and one of the most compelling characters is Seven of Nine, Tertiary Adjunct of Unimatrix Zero-One (Seven, for short).
Her story revolves around trying to fit back into a humanoid existence after spending most of her life assimilated into the Borg "resistance is futile" collective. She's extremely intelligent and physically advanced; she's been stripped of emotion and finds humans ridiculous and irrational. She's just your no-nonsense kind of gal.
In this clip, the Doctor attempts to explain the human mating ritual to Seven.
Seven is in constant struggle with her own humanity and her Borg identity (which is really non-identity, being part of the collective and all, which is sort of like a killer bee hive). She still needs some Borg implants to survive, so she can never make a complete transition back to being human. This, of course, sets up some fascinating ethical dilemmas and personal growth conundrums in many of the Voyager episodes.