The incremental changes to Chrome's UI have been subtle, resulting in very little, if any, friction for the user. The point I was making was a UI that is though

The incremental changes to Chrome's UI have been subtle, resulting in very little, if any, friction for the user. The point I was making was a UI that is thought-through and well-designed withstands the test of time rather well. Details change but the fundamental interactions retain their familiarity. As regards the Windows UI, Windows 7 and Vista were different from XP which was different from Win2k which was ... The introduction of Glass, in particular, caused a lot of frustration for users that were upgrading from XP. Drivers were broken, their applications were borked, etc. Windows 7 fixed all of those problems, but a number of companies have not upgraded from XP because they don't want to deal with re-training their users. In many ways, like Vista is to the Windows brand what the Rapid Release Process is to the Firefox brand. Both ideas caused mass defections to the competition. The jury is still out on how users will react to Metro. The dual-desktop story has two problems: the switch between the Classic and Metro desktops is not very intuitive; people are going to miss the Start Button. I think click-based heat maps should be "a" factor in making UI decisions; not "the" factor in such decisions! Here are my closing thoughts on why a UI change should be as non-intrusive as possible. In my experience, people hate software because it has a way of making them feel stupid. The reason to be careful with changing the UI and/or removing features is that there is a good chance that the changes will people will feel stupid all over again. This is an invitation for defection to the competition.