https://docs.microsoft.com/en-us/windows/deployment/update/w...

As for the opening of you windows after a restart/shutdown that too is a Registry or Group Policy change you can make to adjust its behaviour (They may have promoted the setting to somewhere in the settings app since I changed the behaviour myself)

Basically if you don't want it to reopen your applications / windows when you next log in you make a small change to the shutdown command that executed when you shutdown in your preferred method (If you shutdown / restart with a certain flag windows won't do this).

EDIT: A quick google tells me they have indeed promoted such behaviour to the Settings App.

To change this setting, head to Settings > Accounts > Sign-in Options. Scroll down to the Privacy section and set the “Use my sign-in info to automatically finish setting up my device and reopen my apps after an update or restart” option to “Off.”

AND

launch File Explorer, click the “View” tab on the Ribbon and click the “Options” button. On the View tab, scroll down and locate the “Restore previous folder windows at logon” option. Ensure it’s unchecked or Windows will reopen any folder windows when you sign into your PC.

That's a really great feature. I'd love to see even better window management in 10.

Even a full Shutdown/Restart, I open the machine and boom, Chrome opens and the speakers are blasting whatever I had playing on YouTube the day before.

Shutdowns should be respected. What if I had something inappropriate open before doing the shutdown ?

Apparently Microsoft is doubling down on "we will make things CONVENIENT and you WILL like it!".

I won't restart my chrome now, but i'm pretty sure a YouTube tab will only keep playing if it's in focus.