Everything is funny as long as it is happening to someone else.
We laugh when others do something silly. We're amused when something funny happens to them. But if the same happens to us and people laugh, we might give them the evil eye.
Yet, when others laugh, it can free us. It frees us to see the world through new eyes. Likewise, when we laugh at ourselves, we're free to see ourselves with new eyes. Instead of trying to be perfect, we accept we're human. To laugh at ourselves is to accept ourselves. There's no room for shame when we laugh. We enjoy ourselves just as we are.