This is my Amazon Kindle. It has four buttons surrounding the five-way pad.

Three of them are intuitive: Home, Menu, and Keyboard (from right to left). One is not: Return (the leftmost one). 

Why it isn't intuitive?

• It looks too similar to the Enter key on computer keyboards — it’s just upside down. I wrongly assumed that I could use the button to click a link.
• Because I have only a dozen books on my Kindle, pressing that button simply takes me back to the Home page. Well, we have the precious Home button for that purpose. I will not make a good use of the Return button until I have hundreds of books on my Kindle.

The problem is not in the design of the Return symbol. It is that we are getting accustomed to the almighty Home button on an iPhone, iPad, or any clone products. Home = Return; that is the current paradigm. There should only be one layer between where you are and where everything resides. Amazon should have copied Apple and simply omitted the Return function from their Kindle.

Then what else should replace that button? I think it should be the User-defined button where you can assign a function from a list of options to the button. I can think of some examples.

• Show Table of Contents: very important when you are reading non-fiction
• Swap the Dictionary: a crucial feature for multi-language readers (including this one)
• Enable Wireless and go to the Kindle Store: why let users take two steps to reach the store? Bonus: pressing the same button can return to the book and disable wireless at the same time.