When I was freelancing, I emailed back and forth with potential clients through the Gmail interface. One day I saw this party pic of a 20-something girl with beer in hand, identified by the full name of a receptionist I had emailed with professionally but never actually met. It was a suggestion from Google to connect with her on Google+, which I'm sure she'd have been mortified by. I deleted my account that day.
There are so many mundane variations on that theme, and then there are very serious ones: those seeking support for addiction, as survivors of abuse, or other situations that have social stigma or personal risk attached to them. Some needs are simply private in that way a vulnerable person needs secure anonymity lest the public light itself become a chilling effect, of which health concerns are a common example.
The architecture of Google+ is such that it is inherently inhuman in its disregard for privacy and for applying different "pen names" to the various situations of life.
They may not acknowledge it, but they certainly understand it. The whole value proposition of Circles was initially that'd you'd only share what you want with who you want.
Then Google changed directions entirely (along with the big management shakeup that flipped Google from a bottom-up org to a top-down org) and those ideas were effectively killed. And every single person I knew who'd been toying with G+ dropped it like a hot potato.
I just went to the YouTube comment box, and right there is the control for what circles to publish to: http://imgur.com/3ZEB9Th
Personally I much prefer that G+ (and Facebook, for that matter) lets you interact with real people and not personas.
I just try to explain why Google+ does not work for me at all.
I think Facebook's recommendation system was using the data from other users' address books. As in I'd get a list of various people that I'd done business with in the past as suggested friends on Facebook. Those people had my address in their address book and I can only assume they'd uploaded their contacts to Facebook. Facebook retains that data. Here I am a new user. Wow how does it know I know such and such? I can only assume that it also works the other way: I join and I pop up in their account.
Google got into a mess with Buzz and the address book leaks, and email address leaks.
So there's a fine line here between privacy and helpfulness.
I don't care if it's perfectly legitimate and understandable behaviour, it's awkward.
The Youtube comments used to just be weird as comments would refer to other comments, and then they'd get promoted and end up completely disjointed. At least now there is threading.
If you'd re-shared someone elses video share, you're SOL. I deleted a few of those posts, re-posted others as URL links to the original (this loses comments, if any).
It used to be you could identify your YT comments from within YT. I've got slightly separated accounts on G+ and YT, and the comments originating from G+ don't seem to show under the YT account. I'm not sure there's any clean way to get rid of them.
I pretty much share your view of where my comments get posted -- I place them in a context, and that's where I intend for them to remain. The YT thing was (yet another) huge trust violation. Especially given that comment management tools are so pissedly poor on G+.
As part of the rare breed of people actually using Google+ proper, it's really turned me off from the whole thing. Even though I shared YouTube videos publicly and commented on publicly-viewable Google+ posts with YouTube videos, I intended to only post my comments and shares on Google+, not syndicated everywhere at a later date without additional consent[1] and especially not the cesspool that is the YouTube comment section. I don't really understand why anyone thought that'd be okay. And anecdote isn't data, but talking to other Google+ users I know, nobody seemed to be aware that this was going to happen: they all just thought the identities would be merged, but if you post on Google+, it'd stay on Google+.
[1]: I'm aware that there's probably some clause in their privacy policy that gave them the legal ability to do this, but Google is usually pretty decent when it comes to informing of changes to privacy/visibility options.