The simplest spiritual discipline is some degree of solitude and silence. But it's the hardest, because none of us want to be with someone we don't love. Besides that, we invariably feel bored with ourselves, and all of our loneliness comes to the surface.
We won't have the courage to go into that terrifying place without Love to protect us and lead us, without the light and love of God overriding our own self-doubt. Such silence is the most spacious and empowering technique in the world, yet it's not a technique at all. It's precisely the refusal of all technique.