The 20 different ways of using the Twitter favourite button

What is Twitter’s favourite button for, exactly? What does it mean when somebody ‘favourites’ one of your tweets? When and why do you press the button? 

There are a variety of reasons why people choose to ‘favourite’ tweets. In fact, I’ve identified 20 different reasons for doing so. If you’re anything like me you’ll use the button in a bunch of ways. 

You can be sure that I’ve missed a few things out, so be sure to leave a comment if you use the button in yet another way.

So then, why do people press the favourite button?