Everything you do online when you're signed into Google, and even some stuff when you aren't, becomes a part of your Google profile, but you can wipe the slate clean with these steps.
Something not covered by this guide, and something that can only be rectified from removing yourself from a Google service...is that Google Photos was recently putting the wrong photos in the wrong people's accounts. People downloading their entire photo library were getting someone else's libraries instead. Not good.
Of course, that kind of mistake could happen with any cloud service. They only way to avoid it is to steer clear of orgs that suck up as much of your data as possible.