Honestly, I'm shocked by all the comments here from people without smartphones or only flip-phones, in what's supposed to be a community of technophiles. Personally, I'd be lost without my phone. I don't understand the "addiction" bit at all, it's just a tool to me that is extremely useful, mainly because of a handful of apps. The phone part (for talking) really isn't that important, because I don't talk that much on…
7) camera. Instead of having to carry a separate camera around just in case I see something I want to photograph, I already have one built into my phone that's pretty good (though admittedly of course not nearly as good (particularly for low-light conditions) as a serious DSLR or other good camera). My new phone even has dual lenses, a 16MP regular lens with OIS and an 8MP wide-angle lens. Considering I carry the phone around all the time anyway for the other functions, the camera is a really nice bonus.
Along with this is 8) Banking apps, with check-deposit functionality (enabled by the camera in #7). No longer do I have to take time off from work and waste my time and gas going to the bank when someone sends me a paper check; instead I just take a couple photos on my banking app and it's deposited.