I converted and baptized in 1973. 1975 was all anybody talked about. After the failure quite a number seized on the idea about the gap between Adam's creation and Eve's.
After that, "we are not serving for a date" became a common expression. This was usually delivered with an attitude of "we're better Witnesses than the weak ones who are leaving." Later, everybody treated the whole thing like it never happened.
For a good academic treatise on how this kind of denial works, read "When Prophecy Fails" by Festinger, Riecken, and Schachter. They followed a UFO cult through a failed prophecy expecting to find that people left when it failed. Instead they doubled down on thinking that it was soon, and they'd passed some kind of test. It's an interesting read.