I remember my first smartphone. It was an HTC G1, a big hulking beast of a device compared to my Samsung Sync flip phone. The rest is history, I suppose.
These days I can't get through my day without my phone - calendar and email are the two key functions on it. I track meetings and jot down reminders in it in order to actually remember to do those things. Without it, I miss meetings and have no idea what's going on with my life. It's also my way of keeping in touch with my friends via text and social media as well as being my personal jukebox.
But for all the things it can do, I surprisingly can't live on my device. I prefer browsing the web on my laptop (when it decides to function). Writing on my phone for more than a standard text message or tweet is annoying especially with virtual keyboards (I hate virtual keyboards. Hate them with a passion. Bring back physical keyboards!!). Battery life is also a big problem for me with my device - up until my current device, I basically had to frantically make sure a charger was nearby because my devices would die in what felt like mere minutes after I disconnected it from the charger.
Do I love my phone? Absolutely! (not that any phone is perfect, I do love Android and iOS but they're both painful at times). But it feels more like a necessity because I have to stay connected to the world.