Truthy values are the ones that are not falsy. There are some values that look falsy, but if you look closer, you notice that they are truthy!

Boolean(new Boolean(false)); // true, it's an object.
Boolean('false'); // true, it's a non-empty string.
Boolean({}); // true, it's an object.
Boolean([]); // true, it's an object.
Boolean(-1); // true, it's not 0.