Android permissions are a bit of a mystery to most. You really have to read into them to get a better idea because most sound fairly ominous. What you should look out for are apps that ask for permission that they should never have. Like a game that wants access to your contacts, or a contact manager that needs hardware controls. If you think you need/want more granular control over what app can do what, you should look into an app like Permission Denied. Here's and example and breakdown of typical app permissions:
App: Word Hero
Permissions:
Your location: approximate(network-based) location
Network Communication: full network access
Phone calls: read phone status and identity.
Hardware controls: control vibration
Explanation:
Your location: Grabs a course location from the network to tell usually what time zone you're in. Can be more specific to the actual location of the tower
Network communication: The app will communicate over the internet via your data connection
Phone Calls: The app can read when there is an incoming phone call in order to pause/task switch to the incoming call without disturbing the app.
Hardware Controls: Self explanatory.