From Under the Microscope: A Hidden World Revealed:
This is the kind of comparison that infuriates the manufacturers of electric razors. On the left is a man’s beard hair, cleanly sliced by the blade of a “wet” razor. On the right is a beard hair from the same man, torn and mangled by the action of an electric razor. Since each hair is approximately one fifth of a millimetre in diameter, the difference visible to the naked eye is little or none, and the difference felt by someone kissing is likely to be more imagined than real. Nonetheless, one can see why the manufacturers of electric razors would have preferred it if the scanning electron microsope had never been invented.