Unlike Windows, we couldn't quit opened Mac application by simply clicking on the cross arrow located at the corner of the window pane. I believe this is meant to help Mac users boost their productivity by saving time used in launching applications that is neglected by Windows.
As I've experienced using Windows before, I used to accidentally killing all opened windows while closing application, which I didn't want to, and that's really stressing me.
So, if you're already switching to Mac, be grateful and …