How to re-calibrate an iPhone with a button responds poorly?

Here's a nifty trick to re-calibrate the main button on the front of your iPhone, if you find it does not or poorly answered. All you need to do is follow these simple instructions: 

1. Launch any application preinstalled such as weather, stock prices, ... 

2. Press and hold the power button until "Power off" appears on the screen. 

3. Release the power button and now press and hold the Home button until the "Power off" disappears 

That's it! You will notice that the application closes. You will also notice that the "Home" button is much more reactive.