That didn’t happen, of course. Things never happened the way I imagined them.

The speaker reflects on the gap between expectation and reality: imagined narratives feel coherent and controllable, but lived experience resists that kind of scripting. The flat, resigned “of course” suggests hard-earned familiarity with disappointment—not necessarily tragedy, but the ordinary way plans, hopes, and mental rehearsals fail to match what actually occurs. In John Green’s fiction, this kind of line often underscores a central theme: adolescence (and love, grief, and friendship) is shaped less by the stories we tell ourselves than by contingency, miscommunication, and chance. The quote’s power lies in its simplicity: it names a universal cognitive habit—pre-living events in our heads—and the quiet shock when reality refuses to cooperate.