Thats a good question ;-)
If you're a windows guy, what is the account with the most priviledges...???
No, it's not the admin user as Microsoft doesn't let you to do all what you want on the system.
There is an account called "system" (or at least it was until xp, don't know for later) that gets close to a root user.
You can't login with that user but you all should know that there are enough rabbit holes to get in ;-)
Anyway root means something like beeing the master of your machine.
You can mess up pretty anithing including burning down your house or at least your machine.
There probably wont be any warning signs where you have to click on "accept" and "I know what I do" button.
If you enter the wrong command, you have to live with it and the same applies to granting root permissions to applications you haven't written yourself or at least looked trough the code.
To sum it up: If the wrong one gets a handle to a root shell on your system, you're fucked.