I like thinking of the phone as a super-portable, convient computer that can also handle standard phone stuff (e.g. calling and texting people). It's great for checking email (though I generally wait to get back to my computer if I need to respond), reading news, doing quick searches, casual browsing, sharing videos, listening to music, taking quick pictures, etc. Basically, I have access to that convenience. I might as well take full advantage of it.
I also enjoy messing around with the phone. I've tried out every popular launcher on the Play Store, have flashed a few custom ROMs (though my desire to stick with Android 5-based ROMs sort of limits me right now), flashed a couple non-Android OSs, and done a lot of customization within all of those different areas. Overall, I just like trying out new things, and I've absolutely fallen in love with my phone as I make it more and more of my own device. Sure, it worries the heck out of everyone I know, as they're concerned I'm going to break something, but I love messing with this kind of stuff, and the phone is a rather convenient place to do it all on, especially since I'm not risking losing something I absolutely need for school, especially since it is incredibly difficult to truly brick a phone (and no, a bootloop is not the same as bricking it).
So overall, I probably use my phone a lot more than most in this thread. That said, I'm not really compulsive about checking it either, but that's probably helped a lot by the fact that rarely even have Twitter on the phone, and I never have Facebook on it.