No matter if some people enjoy the feature or not... It's quite appalling. I bought this computer and the copy of Windows.... Like the OP, things happen on on this computer at all hours: backups, scripts, me logging in from home... It should never, ever, ever restart without permission, even if it's just that one predictable day of the month that it wants updates... I understand that many updates only work when the computer is not being used... Fine, I'll restart it right before I go home for the day.
Though work is a Windows environment, I am all Linux at home and am about one frustration away from moving myself to Linux at work as well so that I can actually have control over my computer (oh no! The nerve!)
Nothing should be forced on users (except for by those user's Admins).... Updates, Cortana (ugh), restarts, windows store, links to stupid games in the start menu on "professional" editions of windows... none of it.