I was an avid GNOME user from GNOME 1.x to GNOME 2.2. Like many other users (including Linus Torvalds), I became sick of what I perceive as an "anti-user" stance from GNOME. That is, they ignore their true users (most of the classic, Linux-using and UNIX-using crowd) for some mythical user that in no way represents those who actually use their software.
I'm compiling a list of specific transgressions so I can mention them easily in conversation.
GNOME: Rotting in threes: huge rant…
Sidebar removed from Nautilus in GNOME 3, under the guise of being "really odd and hard to use and inconsistent with every other application", despite other desktop environments and GUIs implementing it fine and users being used to them. As usual, easier to take things out than fix them.
GNOME developer quote of the day collects quotes regarding GNOME 3's new meme: "…not designing a desktop for people…"
How to turn off gnome-terminal's cursor blinking (Chris Siebenmann): GNOME makes it difficult to find the "Disable blinking cursor" option for terminals, making it more and more difficult to find.
Resetting defaults with GNOME programs (Chris Siebenmann): GNOME's gconf system (reminiscent of the Windows registry) makes it difficult to reset settings to their defaults, and is designed to accumulate cruft
In many Gtk/GNOME apps, you may noticed ablank area above selection in GTK list boxes. A popup menu is created with enough space for as many items as possible, but instead of displaying them, it displays a huge blank area.. The list of items appear below that area and may need to be scrolled, which defeats the point of creating a large popup in the first place. I, and everyone I asked, thought this was a GTK bug that's existed for years. Apparently, it's desired behavior (GNOME bug report).
User-hostile bug reports
automatic chat input field resizing should be optional, regression from 2.3 and pidgin: Chat field cannot be resized: according to LWN, this is why Google decided to abandon XMPP. GNOME developers are idiots.