On the Arbitrariness of Swear Words

The setting: my third grade classroom.
Our teacher was walking around the room slowly, armed with a pile of freshly graded quizzes. She came to my desk and laid down my quiz - face down, of course, so that I'd have the chance to review my grade before casually laying it face-up for bypassers to "ooh" and "aah." I turned over the quiz expecting an A, like the cocky 3rd grader I was, and lo and behold, I discovered a "B+" written in vicious red.
I was appalled at myself. Sure, I had the occasional A-, I was fine with that, but I was an A student, not a B student. How'd I let this happen?
"DAMN IT!", I yelled, in my frustration, at nobody in particular, at myself more than anyone. At least that relieved a little bit of my tension.
Our teacher whipped around, raised her finger in the direction of the door, and issued a stern "Wait for me outside."
What? What was this? Was she also as disappointed in my grade as I was? Is this what happens to all B+ students?
I was perplexed. I really had no idea why she'd sent me outside. You, as an astute reader well versed in the ways of the Western world, you likely figured it out. But I, the unaware third grader, just feeling my way in the world, I just couldn't figure it out.
She finally came outside, and I prepared for an explanation that would clear up everything.
"We don't use that word in the classroom!"
"What word??"
"That word that you yelled."
"Why not?"
"It's a swear word!"
"What's a swear word?"
Suffice to say, she was not very happy with me at this point. I was generally a good, obedient student, and suddenly, I was challenging her at every turn.
But I was just being honest. I didn't know that there were words called "swear words", that there was such a thing as "swearing."
You see, my parents were scientists - British scientists, to be specific - and they never got in their heads to teach us the basics of American manners. Thinking back, I can remember only two times that my dad scolded me for the words I used:

• When I called my sister a "bitch", loud enough that the whole house could hear. He didn't care whether "bitch" was designated as a swear word, he just cared that I was saying a rather mean thing. That was fair. (Though she probably did something unforgivable like steal my candy).
• When I answered questions with "yeah." He said that was "unfinished" and "non-committal" and every answer I gave should end in a real sound, like "yes" or even "yep". Yeah...so that lesson never stuck, though I did say "yesh" as my standard reply for a long time, to get around it while still avoiding conformance to boring old "yes". I was such a rebel, aye?

At this point, I'd started to wrap my head around the idea that there was an arbitrary set of words designated as "swear words", but what was in that set? How would I know to avoid them if I didn't know what they were? I could try to ask my parents, but they might just muddle my mind with their British-isms instead. My teacher was not forthcoming with them, but thankfully, my peers were happy to supply a list. And what an expressive list it was!
From then on, I knew not to scream profanities in front of teachers, but I also always had a sense with me or the arbitrariness of swear words. I could never quite take someone seriously when they put effort into scolding about swear words, because I never quite believed there was anything inherently detestable about them. These days, I try not to *over*-use them, but I definitely use them. I use them to get out my frustrations, to express to others the magnitude of my emotions around something, to add impact to a message.
As a linguistic aside: swear words serve a unique function in the English language - "fucking" (or if you're British, "bloody") is one of the only examples of a linguistic phenomenon called "infixation". It means we can infix it in words, like "abso-fucking-lutely", and our brains parse that as perfect English, and there are specific rules that dictate what syllables can be infixed. I know this because we covered it *twice* in the course of my linguistics minor, though my second professor was so reserved that she couldn't bring herself to use the American example. It amused me to see that even a linguist could feel bound by societal rules to not swear.
There's a part of me that wonders if we enforce "no swearing" with kids and in formal settings purely so that we can further enhance the effect of swear words when we use them ourselves. If we never hushed a kid yelling "damn", would we get as much satisfaction from yelling it ourselves? I don't know, but I bet there are linguists and neuroscientists out there that have done all sorts of interesting research on how swear words form, how they change over time, and what effects they have on the brain. (If I wasn't writing this on the train, I would look it up myself, but I will instead leave it as an exercise to the reader).
Back to practical matters: now that I'm working on the programming curriculum for Khan Academy and teaching kids in person, I need to make sure that my lessons and comments are all kid friendly, mother approved. I have no desire to spark a debate with an angry parent on the exposure of kids to swear words, as I don't want to distract from the point: learning programming.
That means that I find myself trying to swear less, or find substitutes for swear words that are just as satisfying and effective. I've already found a few from the community, like the oh-so-visual "Oh My Fried Chicken!", but I have yet to incorporate them into my every day speech. I have to re-train myself to avoid the words that come reflexively to me, the words that are used so heavily by the adults around me, the words that feel so damn good to say. That seems... hard.
But garsh darn it, I'll give it a go… and check back in 10 years to see what the next generation thinks about swearing.