We must understand that the six realms of samsara are not invented or arranged by the Creator or any personified god. Nor are they some chance happenings, devoid of causes and conditions. They are in fact the manifestations of cause and effect. And the most important cause among all is clinging to the self. What does it mean by clinging to the self? For instance, when we have a headache, we say, “I have a headache.” A notion of the self is in that statement. Or, if a car suddenly drives by us when we are riding a bicycle, it would give us a start. Here, a sense of the self is also present in our minds. All that causes this sense of the self to arise is a kind of blind attachment. Attachment may be blind or senseless, but it has completely taken control over every one of us, including those we greatly admire.

- Quote from The Right View, "The Four Noble Truths—the Path Out of Samsara"