I feel like there are a lot of people who don't realize what your phone is capable of doing and also that there are various settings that 'are' in your control.
Just a friendly reminder for those that aren't aware of security settings on Android to go check it out once in a while and make sure settings are adjusted to your liking https://myactivity.google.com/myactivity
Apple users as well- http://www.imore.com/how-turn-off-ios-7-location-tracking-increase-privacy
That's only one 'issue' I know of specifically. Maybe some experienced iPhone users can chime in.
Just showed a friend that every voice search they'd ever done was recorded and saved on Google- they were passing out. While in general many of us are more aware of these things now than ever I think there are still some people out there who aren't.