Happy Mac = Apple Command Key and Spacebar
While holding down Apple Command Key, hit Spacebar and you will see Spotlight search box open up at top right corner of the screen. Just start typing mail and you will see Mail.app highlighted. Hit Enter key and Mail will open. Many times faster than using mouse to open Mail. This Apple Command + Spacebar combination works no matter what app or window you may be in.
Now try doing the same for a any file or document you were working on earlier. Instead of using Recent Items or Finder, simply use Spotlight to open the file.
I used to miss the Start key in Windows. I could open applications pretty quickly just using the keyboard. I thought Mac didn’t offer such shortcuts but I was wrong. You can open Spotlight quickly just with 2 keys and open pretty much any application or file. In fact the Spotlight is even better than the Start key. You can open any file because search is done seamlessly. Brilliant.