A EULA for your app is a great place to protect yourself from liability. You do not want to be sued for a variety of issues. Your end-user might complain that the app isn't as good as they wanted, doesn't do what they wanted, or somehow failed them. Perhaps they will argue that the failure of the app to perform caused them damages. The EULA is a great place to preclue users from suing you for damages.
The EULA is also a place to protect yourself from intellectual property issues. If your EULA allows people to upload photographs or other user generated content (UGC), then you need to make sure that you do not end up being liable for trademark or copyright infringement. All that liability will be pushed back onto the user by a good app developer attorney.
The last thing you need to know about your EULA is that the Apple store requires certain things to be included in order to qualify to get your app into the store. Of course, many of these things simply protect Apple from any liability to either you, the end user, or any third party. It should not be surprising that Apple does not want to be sued as a result of your app, the use of your app by a customer, or some third party that complains about the app's functionality or use in action.
An app developer attorney can assess your business, review the functionality of your app, and help you understand "what legal terms need to be included in your EULA".