Imagine you're a carpenter and you make beautiful furniture like tables, chairs, closets and so on.
And this allows you to buy food and shelter with the money you get from people who want to buy your wooden creations.
But you also make little chairs (think few cm souvenirs) which take you just a few minutes to make and you usually offer them to people you like or to people that you see that offer also something nice like for example a street musician or art performer.
Those little chairs are zaps. That's it.