One of the main reasons we changed rooms (paid to upgrade to do so) at our recent Grand Floridian visit is that we originally had a room with a connecting door and we could hear EVERYTHING the people next door did or said.
I don't think they were particularly rude or noisy or anything of the sort. I think the hotels' connecting door system are poorly built and badly insulated.
They SEEMED to be having normal conversations (not yelling, I mean), yet I could tell you what that family was doing every day. Where they were eating, who they were meeting and what TV shows they watched before bed. They might be able to say the same about me.
The deal breaker, for me, was that they also had a baby, which, as babies tend to do, woke up in the middle of the night crying, multiple times. Which also meant I woke up. And my son. (Not a baby.) Multiple times. Fun!
Again, I'm not blaming the family, but I was really unhappy that Disney charges upwards for $500/night for rooms where you can hear people carrying on conversations next door ... And then told me the only way I could move was if I wanted to pay an outrageous amount to upgrade. After further discussion and time a "complimentary" move was offered, as was a more reasonable upgrade cost to a slightly larger room (instead of a suite, in another building no less, which was all they originally said they had ... And wanted another $700/night for). We ended up going with the larger, deluxe room and paying a bit more for (>$75 more per night).