No matter how meticulously a man grooms his beard or mustache, trims his eyebrows, or shaves whatever part of his face is not hirsute, there will always be a few defects that can only be detected by glancing in a car's rear view mirror while stopped at a red light. The few whiskers that grow way up high on your cheekbone and are now a half-inch long. The two hairs that grow on the tip of your nose. They simply don't show up in bathroom mirrors. Only in cars.

And it doesn't apply to men only. That one hair that grows on a woman's chin and is now an inch long.... Same deal. It only shows up in a rear view mirror while stuck in traffic.

It's a law of nature on the order of The Third Law of Thermodynamics. In fact, it's The Second Law of Personal Grooming. The First Law of Personal Grooming is, of course, that a mustache trimmed at 22:30 will be lopsided. And The Third Law of Personal Grooming is that any defects discovered by glancing in a rear view mirror will be forgotten by the time one arrives home and, therefore, will not be corrected, only discovered anew the next time one is patiently waiting behind a stopped school bus.