You could sit your girlfriend down with nothing but terminal, the man pages for a printer or video card driver, and the root user password, and she'll understand why Windows is better.
One of them is "Automatically trust WiFi connections my contacts trust", a bunch of others are sending data to Microsoft. It's been a few months since I turned on a new Windows 10 PC but I was completely turned off by the advanced configuration.
The #3 story on HN right now is "Windows 10 in-place upgrades are a severe security risk"
I thought this was a good read the other day https://www.brokenbrowser.com/abusing-of-protocols/
It just seems terrible security wise, the OS itself is spyware.
That is to say, I was excited to be trying out a sexy new Asus Ultrabook with Ubuntu mixed in but didn't care to try after setting it up.