What smartphone feature do you never use? I was putting my phone in my car dock this morning, like I do every morning and I noticed a hole on the top of it. For a second I thought "I don't remember that being there" and then I realized it was the headphone jack. It occurred to me that I NEVER use headphones with my phone. I have a separate device (okay, it's an iPod -- 3rd generation nano -- the square one) that I use for tunes with a head set.