The only time I ever get freaked out by how much different companies know about me is when I see the data they have visualised. If you want to freak yourself out all over again about GPS info, Google's location reporting service still allows you to visualise on a map everywhere you've been in the last 30 days. Here's a reminder on how you do it.
Head over to Google's Location Reporting site and familiarise yourself with how Mountain View hoovers up info about your location data, then scroll down and access the map view. You'll then be able to have a look at your location reports on a daily basis or over the last 30 days. Above is my last 30 days. Whee!
Of course, if this sort of thing freaks you out too much (it really shouldn't), you can always delete your location history and turn off location reporting on your phone.