This reminds me of Joel Spolsky's take on UI. "A user interface is well-designed when the program behaves exactly how the user thought it would."

Never once while manipulating tabs in Chrome have I done something and then asked, "Now why did that happen?" The tabs do what I expect them to do so I don't have to think about them.

As a side note, I also find the "duplicate" feature in the right-click menu useful, something at least Safari lacks.