It has been a misconception that CFD of commercial fluidized and circulating fluidized beds is only in its infancy. Indeed, codes and computers are fast enough to now simulate large-scale unit operations in a reasonable amount of time (i.e., weeks). However, CFD has been used for over 20 years in the application with significant impact. Today, CFD is being used for a wide range of industrial applications and targeting complex problems in the industry such as NOx emissions, particle attrition, erosion, maldistribution of feed gases, debottlenecking, etc. Yet, a successful model stems from how well the modeler and stakeholders understand the fundamentals and the constitutive equations used for closing those fundamentals. A lack of this understanding has never changed in the last 20 years, and has resulted in the tarnishing of a valuable tool (CFD, DEM, DNS). In other words, the promise of higher order modeling is confounded by a myriad of mistakes including not understanding the underlining assumptions and the limitations they come with, oversimplifying boundary conditions, ignoring transient versus steady-state behavior, and not realizing the benefits of a poor fit. All of these issues have been the result of failed opportunities that should have been identified at the very least in retrospect. This presentation will focus on the some of the gaps that a modeler often misses or opportunities that were never capitalized.