I set the scene for my discussion by explaining my reading of Nancy VanDerHeide's (2009) article, her analysis of mirroring, and her view of the essential qualities of dynamic systems theory. Focusing on the vignette of Molly, I discuss the unpredictable event described by Nancy. Following Meares (2001) and Bromberg (2006), I emphasize that we can tell whether or not an act has been transformative and mirroring only by what happens next. In this case, there is expansiveness and an increase in what Stern (1985) called “vitality affects.” I amplify and highlight what is already present in Nancy's piece and suggest some principles deriving from her descriptions, which may be used as guidelines for clinical practice.