MPDGs are usually static characters who have eccentric personality quirks and are unabashedly girlish. They invariably serve as the romantic interest for a (often brooding or depressed) leading male protagonist.
Kate Winslet's role in Eternal Sunshine of the Spotless Mind has been suggested as the anti-MPDG, realized in a remark to Jim Carrey's Joel character: "Too many guys think I'm a concept, or I complete them, or I'm gonna make them alive. But I'm just a fucked-up girl who's lookin' for my own peace of mind; don't assign me yours."