Why Brishna doesn't save her work

I am not a graphic designer, but I do have some designing experience. And my sister is a designer. She is not a pro yet, but she's on her way to be. In her school, they teach her stuff like story boarding in Illustrator etc. And well, anybody who has ever done something like that, or has written long essays on a PC, knows that when it crashes, and you lose all your work, it feels like there is no point to being alive anymore...

*dramatic pause*

As for me, I have developed a habit of constantly pressing Ctrl + S, with my left pinkie and its neighbor, so much so that while filling forms in those websites that require you to sign up, I constantly find myself closing the Save as html pop-up which opens up when you try to ‘Save’ a web-page. 

Anyway, when my sister had to leave her computer in the middle of some designing and I started using it, she always asked me to first save her work, then carry on. And when that happened a number of times, I asked her why she doesn't save her work every minute, like I do. To that she said that Z and S are so close, that when she tries to press Ctrl S, she sometimes presses Ctrl Z, which makes her lose her work instead of saving it. 

She didn't know about Ctrl Y.

She is in debt to me since then :)