To summarize, large systems can display qualitatively different behavior due to their size and extensive dynamics simulations are essential to uncover them as we demonstrate on an example of the Diels-Alder reaction of C60 fullerene with 2,3-dimethyl-1,3-butadiene. These simulations are now possible with efficient active learning implementations and should become standard. Our study unveiled the crucial shape of the barrier shape and noncovalent interactions that can lead to prolonged alignment phases including complex dynamics behavior before the reaction happens.