4. Keiko O'Brien
Oh dear God was a character ever so superfluous as Keiko? Her sole task on Deep Space 9 seemed to be to nag and/or support Miles, and to bring his two children into the world. She never had a storyline of her own, apart from being held hostage at one point by aliens, and even her wedding day thunder was stolen by Data. I used to cringe when I would see her name coming up on the credits at the beginning. And why was her face almost permanently set in a sort of half-scowl, half-puzzled look, a bit like Lucy Liu? What ever possessed Miles to marry her anyway? Was it just so that the two cultures (Japanese and Irish) could clash in an amusing way? Well, they didn't! Nobody got a kick out of their relationship, except maybe Julian. Talk about peripheral...