I hate how long it takes for them to move. They tell you days in advance and then you have to ignore them until they move so they don't end up changing their mind.
Ugh, so frustrating! I preferred it in Wild World when they would randomly just pack up and either you told them to stay or not to stay. If you told them not to stay, they were gone the next day.
The opposite's happened to me. In my old town Freya asked if she should move and I CLEARLY remember saying no. three days later she was all packed up....
Nate wanted to leave and then I said Yes and he was like "Maybe we never got to be friends so I will stay for another while". I hate when they do that.