Google Play Apps with 10M Installs Drain Batteries, Jack Up Data Charges

>Am I infected? The best method is to check installed apps for high data usage...

I go out for lunch, do not use the phone at all, come back, and Google Play Services itself has used around 25MB. The incessant phone home even while not on WiFi drives me crazy. Maybe it's some app that's asking for data from Google Play and Google gets it and does a handoff, but it's the service being blamed for the usage. So I don't really know how to find out what's instigating the usage.