Exactly a Door, I'm a Monad.

It's like having a little box where you can pop your function in, close the box and just let it explode safely. And then if it exploded, then fine, it did it inside the box and we're safe. It's without littering your code with it, right? Like we've written code back in the day that was ugly like that. But yeah, you get the idea though, it is a way of separating out the actual function you're executing from the environment in which it executes. If you want a slightly grand way of thinking about it, I'm considering the state around which I execute this thing.