Favourite not-so-obvious features

They are near. Features that you wish you had. Often a function is implemented in a not so obvious way or you just don’t know about it.

I dare to call them the “not-so-obvious features”:

• KWin (KDE’s great window manager) supports smart maximize – left click on maximize to… well, maximize. But right click on maximize to maximize horizontaly only. When clicking with the middle mouse button the window will maximize verticaly. Really great stuff 🙂 .
• Jumping between words works by pressing CTRL and left or right. Awesome for correcting mistakes swiftly (although I never do, my way of speaking/writing is considered art).

What are your favorite not-so-obvious features?