Quantum researchers are developing increasingly sophisticated compilers and optimizers that will help usher in the quantum revolution. How close are they to achieving optimality and what does that even mean? I will discuss three standard notions of optimality, show some optimal quantum programs, and present a technique for proving optimality. My presentation is based in part on the following 2024 paper, https://doi.org/10.1016/j.laa.2024.03.039