Pluck Yew

Mr. Rogers cracking up as he leads
some kids in Where Is Thumbkin

Many years ago, I was shoveling my folks' driveway after a big juicy snowstorm. As I stood near the end of the driveway, a car came careening down the street far too fast, considering, and nearly hit me. Enraged, I flipped him the bird, a gesture that would have had more impact had I not been wearing mittens.
The one-finger salute, a favorite among punk rockers and driving enthusiasts, is an obscene gesture meant to represent... penetrating someone with a teeny tiny weenie or something. According to Snopes and Mental Floss, no one is exactly sure where the gesture was born, but it's way older than I would have thought. According to Mental Floss, the gesture was a favorite of Caligula, who liked to make his enemies kiss his middle finger, but considering Caligula's proclivities, having to kiss dude's middle finger was getting off easy. 

If you're ever in Turkey, it would be best not to play I've Got Your Nose with the locals - the gesture, known as the fig, is only "mildly obscene," according to Wikipedia, and generally means bugger off. Fig in this sense appears to be etymologically unrelated to the sex act known as figging, which I'm neither going to describe nor present the etymology of. Oh, I know the etymology, but, you know, my mom's reading this. Hi Mom.
In American sign language, this gesture isn't rude at all - it's the letter T. Twist your fist and it means toilet. Dante wants you to know that it is not acceptable to give God a fig. When a dude did so in The Inferno, he got strangled and gagged by some snakes. Been there done that, I tell ya. In ancient Greece, the gesture was used to ward off the evil eye.
And speaking of the evil eye, let's talk about throwing the horns, a gesture once synonymous with heavy metal and now, well...

During the Satanic panic, it was thought to represent devil horns, or the number 666... somehow. However, to the metal singer who popularized the gesture, Ronnie James Dio, it meant no such thing. He picked up the gesture from his Italian grandma who used it to ward off the evil eye. (Special thanks to Tony for bringing this to my attention).
The evil eye, by the way, is when someone curses you by looking at you funny. According to Wikipedia, a ton of cultures all over the world believe or believed in the evil eye. Different cultures have different names for it, but my favorite is the Hawaiian maka pilau, which translates loosely to stink eye. 

But let's wander back to the old devil horn gesture. This, too, has lots of different meanings. It wards off the evil eye, of course. It can mean bullshit, I guess because bulls have finger horns? Another creature with finger horns: a guy who's been cheated on, of course. In old timey Europe and current timey Italy, the gesture is used to indicate a guy's wife has been unfaithful. Wikipedia says that it's a reference to the mating habits of stags. The term cuckold, by the way, comes from the child-rearing habits of cuckoo birds (or lack thereof). Many types of cuckoo birds will sneak into other species of bird's nests and lay their own eggs. The other bird comes back to her nest and doesn't notice a thing... until the cuckoo hatches and systematically murders all the other birdies because seriously, nature? Seriously? So a cuckold is a dude whose wife has someone else's bun in the oven, so to speak.