Sometimes, yes—but not simply because the lens is “fast.”

When two lenses are both set to f/8, the wider maximum aperture does not directly make the image better just because it can open farther. The main reason faster lenses often look better is that they are often designed and built to a higher standard, with better correction for aberrations, flare, contrast, and other optical issues.

A fast lens stopped down may outperform a slower lens at the same working aperture because it is using a smaller, better-corrected central portion of the optics. For example, an f/1.4 lens at f/2 may be better corrected than a lens whose maximum aperture is f/2. But this depends entirely on the specific lenses being compared.

There are also practical advantages: autofocus usually happens with the lens wide open, so a faster lens can improve AF performance and make manual focusing easier, especially in low light.

At small apertures such as f/8 and beyond, diffraction also starts to reduce sharpness, and different lenses may handle that differently.

So: you’re not necessarily fooling yourself, but the difference is usually due to lens design and quality, not maximum aperture alone.