Yes, this. Location services. Good luck keeping that off if you use any maps for navigation. Google accounts... Good luck using Android apps securely without the Play store.
I tried rather hard but was ultimately unsuccessful in using Android in any convenient way and not allow Google to track everything I do. If you have any suggestions I am still all ears!
If you "opt out" it cripples locations for third party apps. If you opt in Google tracks your location.
Google Accounts.
If you don't put a Google Account on your Android phone it cripples, well, everything. But if you do put a Google Account on it then Google tracks the IP address when it connects to the internet as well as sync times/login times/etc.