Not to be snippy, but that's about as helpful as my ISP telling me to reboot my computer because the cable modem is broken.
Now, if you want to talk about methods of finding out what app might be causing problems, or if you know of a particular app (or set of apps) that cause problems, please let me know. If you're just telling me that I'm doing something wrong without any constructive help, well, it's obviously not that helpful.
For the record, I have installed apps and made phone calls with my N3, but I have not, and will not ever, wipe my ass with it.
There are over a million apps in the Play store. Only you know which ones you've installed.
It's a little difficult to tell you which app might be causing a problem without a complete list of your apps, assuming I have the time to read through the reviews of each one in the Play store.
If you've ever had an app crash, that's a good place to start.
If you've sideloaded an app (by running the .apk because it wasn't available in the Play store), that would be my second choice.
If you've installed an app from the Amazon Market because it wasn't in the Play store, third.
Check Settings, application manager, running, and consider uninstalling any apps that weren't included in the stock release.
If you've installed an app to benefit from a feature that your carrier would otherwise charge an extra fee for, that's another uninstall.
If your phone is rooted, see the "all things root" subforum sorted by carriers.
I'll add to this list if I think of more ways you may have caused this.
I kid.