The very first thing that I was taught in university about UI design is that there is no way to make a UI that is universally understood because of the variety of experiences and backgrounds that users have. We all come at the world through different paths and though we tend to feel that we all think in similar ways, our thoughts and internal processing vary widely.
So, UI designers try to find a happy medium where most users will understand what they should do rather naturally, but there will always be a significant minority that will need to be educated and will need to adapt to the UI. It’s just the nature of people and UI design. Even a simple green button to indicate how to start a machine or process isn’t meaningful to everyone. Consider people that don’t drive. Green is just another color to them. Consider people that are colorblind. They might not be able to discern which button is green and be unable to start the system.
I too was a little confused at first with the new tab layout, but have adjusted to it so I can live with it.
The last thing that I’ll offer is that if you never fail, you’re not actually trying! The designers don’t always get it right, but at least they are attempting to find better ways of doing things. Think of the original iPhone and how many UI paradigms that it shattered and how many new and intuitive elements it introduced. Something to think about.