It's why the line "the nature of our immortal lives is in the consequences of our words and deeds, which go on pushing themselves throughout all time" (from Cloud Atlas) is the most profound quote to me, and I even had it tattooed on my spine. Once you realise that your Self is literally made up of all the intersecting ripples of everyone else's choices, you realise unity isn't just a concept, it's reality. The singular self is an illusion.