In the first season, she uses to hang around the office when she’d stop by to have lunch with Mary, and overstay her welcome. It drove Lou nuts that she’d get everyone involved in personal conversations.
Lou softened up a lot as the show went on.
Rhoda could be annoying. I didn’t read it as a child, but when I saw some reruns a few years ago, the writers have definitely written in a clash between Rhoda’s New York way of dealing with people, and the fact that the show take place in Minnesota.
Plus in that episode they’re trying to sell Rhoda as the housewife type while Mary is still the girl-about-town. In othercontexts Miss Harper looked even better.
The problem is the classic best friend pairing often has little to do with actual looks. It’s got more to do with wearing the newest fashions and conforming to everyone else. Plus as others have noted often the “unattractive” one was more acurately the “ethnic one” (often the Jewish looking one). Considering up until the late 60s many Jewish actors tried all they could do to hide their background, one wonders if that was a subliminal factor. The more common male focus on breasts/legs/bottoms isn’t really considered.
Or maybe it wasn’t subliminal. Rhoda it the one who does most of the saying that she’s less attractive than Mary. No one else, other than Phyllis, who openly dislikes Rhoda ever really says it. Rhoda gets plenty of dates, but when men prefer Mary, it usually has to do with responding to her self-confidence.