Here's how you can use the power button on your Macbook to quickly turn off its display in OS X Mavericks.
1. Push the power button for one second, this will turn off the display on your Macbook.
2. If you push it for about three seconds, you'll see the shut down menu appear.
Using option #1 is a quick way to shut your Macbook's screen down so you save power. It's certainly faster than waiting for the display to turn itself off via the power settings.
Read more: Tips and Tricks in Mavericks