> Oh also the + button didn't do full screen as today, but... it did... something. I never understood the point of the + button.

When I first came from Windows I was confused about this as well, but once I got the hang of it, it became the most logical thing to me.

The green + button zoomed the window to the minimum window size that showed the full content. (For example, one page in a word processor or one slide in presentation software.)