Every so often an application will misbehave and crash, most of the time the program will recover and you will be on your way. Every so often an application a program will crash and it wont recover, and will be in the eternal state of Not Responding. As a result you may want to force quit a program and open the program up again.
The usual route to Force Quit an application would be to open up Activity Monitor, go to the CPU processes, find the application, click Quit Process and then Force Quit. This is a long process, and if you need to quit an application in a hurry, this takes time. Another option is to right click on the application in the dock, but most of the time this doesn’t work because the application has locked the dock icon.
The quickest way by far I have found it to press Command + Option + Escape. This will bring up the force quit dialog box. This simple command will open this box nearly all of the time. You can also access it from Apple Menu > Force Quit Applications.
A couple of clicks and the program is closed. Very useful if you have a time critical application that is running and you need it closed. For example if you have a program using 200% of the CPU when you are on battery, you need that application closed as soon as possible.