Most Eyeglasses were not made with your face in mind
Once upon a time, you spent a few hours at your optical shop, trying on dozens of frames and "just settling" either with a pair that looks great but keeps sliding off your face or one that fits fine but you won't be caught dead wearing it out. You end up wondering what is wrong with your face; why your face is so flat, why you lack a nose-bridge, why every frame seems to sit on your cheeks, and why it's so hard to find glasses that hits the right balance of fitting right and looking great.
It's not you. Most designer eyewear brands only cater their eyewear collection for people who have higher nose bridges so the plastic frames are not designed for flatter face individuals. They will sit awkwardly faces with a low nose bridge, aka the space between your eyes.