At bottom the world isn't a joke. We only joke about it to avoid an issue with someone, to let someone know that we know he's there with his questions; to disarm him by seeming to have heard and done justice to his side of the standing argument.
We die to each other daily. What we know of other people is only our memory of the moments during which we knew them. And they have changed since then. To pretend that they and we are the same is a useful and convenient social convention which must sometimes be broken. We must also remember that at every meeting we are meeting a stranger.
Interdependence is a fundamental law of nature. Even tiny insects survive by mutual cooperation based on innate recognition of their interconnectedness. It is because our own human existence is so dependent on the help of others that our need for love lies at the very foundation of our existence. Therefore we need a genuine sense of responsibility and a sincere concern for the welfare of others.