Fortunately, the phone comes with many of these features already turned off, and you can turn off others you don't need or want.
It took me a while to figure out that the Wi-Fi connection on my phone kept mysteriously turning on by itself because of some feature called Smart Mode.
So Smart Mode is now off.
Group Play is a feature that lets you share music and photos with other S4 users on the same Wi-Fi network.
But I don't know of any S4 users, and it doesn't work with Group Play on the S III.
I couldn't uninstall the app, so I buried that in a new folder called Junk.