"I get accused of giving very long answers, so here's a short one. Shaving against the direction of hair growth gives a closer shave, but has two drawbacks:
It's a good way to donate blood, and you run a high risk of cutting off a hair below skin level, causing an ingrown hair--the whisker grows into the surrounding tissue instead of out of the pore, resulting in inflammation and possible infection.
To avoid these problems, shave 'with the grain' (that is, in the direction your hair grows.) Each person's facial hair has its own growth pattern. If you are unsure of the direction of your beard, let it grow for a day or two and you'll see it.
Professional barbers, by the way, usually first shave with the grain, and then re-shave going sideways. I asked Cecil if there was enough money in the Straight Dope Research & Entertainment Fund for me to go to a barber so I could report back firsthand, but no dice."
Nick says: It's crazy to me that I can become something of an authority on chondrocyte mechanotransduction, information which may never come in handy again... Yet the basics of shaving, which I do (nearly) every day, remains a mystery. Where are the priorities? More echoes of Dusty, who likes to investigate his groceries and other purchases. Why know about esoteric medical facts if you don't know what you're eating, why you're shaving against the grain?
So, more trivia: "Facial hair grows about 15/1000ths of an inch each day, or almost 6 inches a year. Shaving removes about 65 mg of whiskers daily, per male (on average). If you prefer, that's about a pound every 16 years. In the U.S., sales of razors (as distinct from blades, replacement cartridges, etc.) is around $90 million annually, of which about a third is for electric razors. . More than half of wet-shave razors that are sold are disposables. Total sales of replacement blades is in excess of $900 million, which is why the razor blade companies sometimes give away the razor. Who cares about the razor? They want to get you hooked on the blades."