I haven't heard many people express dismay or annoyance with the UX in their software. Certainly their software doesn't "look" great and I think that's what a lot of people are referring to when they talk about Google's terrible UIs.
But the fact is, most of the UIs do what you expect and get out of the way without making a bug fuss.
It's not just how it looks. To pick on my favorite tool, Google AdWords: you select a campaign, then you select the keyword tab, then you click on "add keywords", then it asks you which campaign you want to select... Didn't I just tell you that 3 clicks ago? Why do I have a choice again? That's an example of poor UX design.
But the fact is, most of the UIs do what you expect and get out of the way without making a bug fuss.