Users Don’t Hate Change. They Hate Our Design Choices.: In software that gets day-to-day jobs done, UI changes can have a considerable impact on the productivity of users, and thus, they’re emotions towards that software. Everything about the introduction of the "new" WordPress editor (a.k.a. Gutenberg) in 5.0 and most improvements that were done since then in subsequent releases, fall in this category.
@cliffseal has brought up many good points about the communication around the Gutenberg release.