The other family was only there during the summer, which meant that we had all fall, winter, and spring to forget that we shouldn't just answer the phone as soon as it rang. I assume this was annoying to Single Ring Family, but I don't think we ever talked to them or even knew who they were.
Another value-added service that we never opted for was touch-tone dialing. For a long time we used those old rotary phones that originally were leased from Bell, but they gradually became more and more decrepit (I remember that we had one that for a while if you pushed on the dial too hard the section of the phone that the rotary dial was on would swivel into the phone) so we eventually got pushbutton phones, but we still had to flip the little switch that would make them pretend to be dialing.
I think the phone company eventually just stopped offering a party line as an option, but it's possible that it was another one of the sweeping changes introduced by my stepmother in the past five years or so. She also got my father to finally buy a toaster.