Sometimes while you on running an application (from the App Store or even like Safari ) can start taking up so much memory that it starts to decrease the performance of the device.

Especially with all of the new App Store applications coming out, sometimes you just come across a bug that will freeze up an application and it won’t even let you quit it the normal way to get back to your home screen/SpringBoard.

While the application is open (the one that is causing the problem), and application is couldn't run or freeze up. Just press and hold the home button. Holding this home button for about 10 seconds will force that app or game to quit.