Like any smartphone, your iPhone may freeze every once in a while. While incredibly annoying, it’s not a reason to toss it against a wall as hard as you can. If your iPhone isn’t responding to any of the tap inputs, you just need to restart the good old fashioned “choke it to death” way.
To do this, press and hold the power switch and Home button at the same time. Keep holding them until the screen shuts off. It takes roughly 10 seconds before this happens, after which the device will reboot and display the Apple logo. This is the most extreme way to reboot your iPhone, so try not to use it too often.