Generally speaking, elegance and simplicity are markers of finding the theoretical path to a grander truth, while messiness or complication is the signifier of having an incomplete or flawed understanding of the issues at hand. Though there are many who would argue against applying this idealization of “beauty” in the sciences, it should be remembered that our perception of beauty was classically quantified and rationalized (think phi and golden ratios) well before anything as arcane as particle physics could exist.
With this in mind, observe the practical, beautiful simplicity of the “amlituhedron” quantum jewel. A theoretical breakthrough coming out of Princeton, this geometrical understanding of particle interactions has made previously uncomputable equations solvable with good old pencil and paper. And if that isn’t tantalizing enough, the math suggests that locality, unitary, dimension, and even space-time itself could be flawed as basic assumptions for the interactions of elementary particles.
Be prepared to have your mind blown.