I LOVED my iPhone 4 & iPhone 5 back in the day. I thought they were just perfect. I could reach all the keys, they fit in any pants, and they were just my favorite era of phones ever. Metal edges, glass front and back, no stupid camera bump -- perfection. For the time they existed, there was nothing to improve on those phones.
But I pretty much hate my iPhone Mini. And it has almost nothing to do with the phone -- it's basically an improved version of the iPhone 4, except now it's got a stupid camera bump. And I would still love the form factor, but like... so many things just don't fit right.
Apps just haven't been tested to work on it, especially if you tweak your default font sizes at all, and it's just a sub-optimal experience in almost every way. My fingers fit, but now websites are built with bigger fonts and need bigger screens. I passionately hate "viewport wobble" and you see it all the freakin' time on the iPhone Mini.
Book an Uber? The buttons are off screen, or weird places. Sure that's the app's fault -- and frankly a lot of apps need to do better for responsive design in order to better improve accessibility (especially for elderly users!) but that's a bigger fight than I want to get into when I pick up a phone and just want it to work.
So I don't know, like if I had a magic wand and could just zap every website, every app into compliance with the slightly smaller screen... sure it'd be great. But I don't, and that makes for a frustrating user experience that, frankly, ruins the iPhone Mini for me.
My iPhone 4 was the best phone I ever had. Hands down. Loved it, emotional memories of it are still very fond. Wish I could find that again, really do.