The Third Agreement: Don't Make Assumptions. Are you aware that almost everything you tell yourself is an assumption? Humans have a powerful imagination, very powerful, and there are so many ideas and stories that we can imagine. We listen to the symbols talking in our head. We start imagining what other people are doing, what they’re thinking, what they’re saying about us, and we dream things up in our imagination. We invent a whole story that’s only truth for us, but we believe it.