But Trillian? I’m not so sure about Trillian. Even when nobody’s making a hash of her, even when a master like Susan Sheridan is giving her the best possible read, her role is kind of “the girl who’s there, but smart.” And that makes her vulnerable to predation by hackish tropes. Why not have her walking around the bridge of the Heart of Gold in a backless plunging leotard? Why not develop an offensively goofy romantic subplot where she helps Arthur learn to carpe the diem? Trillian wouldn’t do that, you say? How would you know?
When female characters are whole, real, singular people, they are to a certain degree inoculated against these banalities. When they’re skeletons, though, someone will be more than happy to flesh them out with whatever stereotype is currently preferred. Women characters are always under attack by hackneyed ideas; without an interior, they just collapse under the weight.
–Jess Zimmerman on The Hitchhiker’s Guide to Female Characters.