Abstract This paper argues for a Work-Centric, Operational interpretation of electromagnetic radiation (EMR) grounded in operational physics and thermodynamics. It maintains that while photons are properly described as quantum excitations of the electromagnetic field, their physical meaning becomes operationally significant only at irreversible interaction events. The manuscript distinguishes between propagation as a mathematical description and interaction as the physical instantiation of energy transfer. The central claim is that all causal efficacy attributed to light occurs at interaction. The "Yelp" Effect (Non-Linear Orbital Recoil): > Within the Operational Threshold Principle (OTP), the "Yelp" is defined as the instantaneous, non-linear physical response of the space-time substrate to a sudden influx of thermodynamic work. While General Relativity treats the geodesic as a static, passive track, OTP recognizes the metric as a dynamic "leash." When a high-energy transaction (such as an X-class solar flare) occurs, the sudden tension on this leash causes a measurable "shiver" or recoil in the orbital residuals of nearby bodies. This is not "instrumentation noise," but the audible "yelp" of the substrate maintaining the constancy of c under load (the 'yank' of the leash).