I wonder this, as smartphones are maturing into what may be their final form: bezel-less slabs of glass with high-res screens, microphones, and sensors, that all look pretty much the same. The iPhone 8, for example, is the fourth generation of iPhone with the same basic form factor. A few years back, this would have been unheard of. A few years from now, though, I wouldn’t be surprised if there still is a “legacy” iPhone out there with this form factor, discounted several hundred dollars below what the iPhone X form-factor phone of the day will cost.

If all smartphones have the same basic shape, does it even matter which one you have? I think it does. You can still hate one phone and love another with the same case design. There are other things that matter, beyond the obvious distinction in operating system and/or Android skin. My experience with the iPhone 6S vs. the iPhone 7 is a case in point.

Nearly identical phones can be vastly different

Last September, I traded in my one-year-old iPhone 6S Plus for an iPhone 7 Plus, though Apple’s iPhone upgrade program. I hadn’t originally intended to do this. I had always kept my phones for two full years, and I chose the iPhone upgrade plan to get a nice monthly payment that also included AppleCare+.

The reason why I upgraded last year is that, after a year with it, I decided that I hated the iPhone 6S Plus. My 6S Plus was fine, and I never had any problems with the hardware or software, but I never really liked it, for several reasons. First, it was big, and I wasn’t used to big phones at that point. Second, it was ugly: the space gray aluminum finish was dull and drab. Third, it was ungainly: not only was it a large phone that strained my hand and my pockets, but its edges were smooth and slippery. Its Apple leather case was awful, too: it had mushy, hard to distinguish buttons, and its patina became slick and unpleasant after only a few months of wear. (Yes, I know the leather case is not the phone, but as it was an Apple product released alongside the phone, I think it is fair to include it in my assessment here.) The phone’s camera and software ecosystem were great, but it didn’t feel good in my hand, and that is crucial to how attached you can get to a handheld device.

While I grew to hate the iPhone 6S Plus, I quickly grew to love the iPhone 7 Plus. This surprised me, because the 7 Plus is basically the same phone. Sure, it has several major improvements—most notably, dual rear cameras and a much faster processor. Its minor improvements, however, contribute a lot more to my love for it. First, it looks great: the black finish is gorgeous and even blends seamlessly with Apple’s black leather case. Second, it feels great: I like the feel of the back much better, and the Apple leather case that came out with it has better quality leather, and clicky buttons on the sides. Its Taptic Engine, which provides force feedback for 3D Touch, the home button, and various user interface interactions, is absolutely amazing. It makes certain interactions, like scrolling picker views, 3D touching app icons, or pressing the home button, feel like you are interacting with actual, three-dimensional objects. It doesn’t vibrate as much as tap you with a reassuring, nearly soundless thud. The force feedback feels so good that it is almost addicting. It’s the kind of thing you would never think is important before you have it, but you don’t want to live without it once you do—like having heated seats in your car, for instance, or even the Apple Watch.

It isn’t just about the iPhone

I have the Essential Phone, now, too, which runs Android. I love it, too, though not as much as the iPhone. Why I love it, however, is a similar story to the one above, but it takes into account other manufacturers’ phones as well.

The Essential is one of a new breed of “bezel-less” phones. (These phones all still have bezels or notches or cutouts somewhere.) It is a smaller phone with a larger screen, much like the iPhone X, Pixel 2 XL, and Samsung Galaxy Note 8. Its lack of bezels make it smaller, and therefore easier to hold and pocket, than my iPhone 7 Plus, and other flagship phones of yesteryear.

Its glass screen and ceramic back make it like an impossibly smooth and cool piece of jet black soap. Its flat sides and smooth edges make it just grippy enough to feel secure in the hand, as opposed to slippery and droppable. Holding it, rather than using it, is the luxurious part of the experience. It feels just fantastic in the hand.

It doesn’t hurt that it has snappy performance as well—but you could get that from other phones as well. In fact, I vastly prefer it to the Samsung Galaxy phones and Pixel phones (the last generation, alas) that I’ve held. While those are the top Android phones in performance, hardware design, and features, I just don’t like them. It’s hard to put my finger on exactly why, but the materials and case design do not suit my tastes at all. They feel icky to me, in a way the Essential Phone never did.

The emotional connection

It isn’t 100% rational what makes a piece of technology suit you. It’s emotional. And sometimes the most subtle things—such as the color and feel of the materials, or the quality of the haptic feedback—can make you love a phone, or hate it.

Great haptic feedback is a major contributor to why the iPhone 7 Plus is my favorite phone. It feels great, and it feels alive when I touch it. I didn’t expect that feature to even matter to me, let along bind me to that particular model of phone. But it did. I don’t think most handset manufactures get that. After all, feeling is not a checklist feature.

I think Apple does get it, and little things like the Taptic Engine feeling so different than anything else are intentional parts of their industrial design and marketing strategies. Their industrial design and marketing teams have started (first, in my opinion, with the Apple Watch, and then with the iPhone 7), to really concentrate on what makes personal technology personal—that emotional connection you can have to your devices. And what they are doing is certainly working on me.