One of the more advanced human communication skills that humans have to master is the subtle art of keeping your foot as far away from your mouth as possible. In other words, knowing what you’re expected to say in a given situation, and, more importantly, what you’re expected not to say.

For most right-thinking, socialised humans, this comes pretty naturally. The rules are myriad, but simple. Don’t accuse your boss of farting in the elevator. Resist the impulse to call your great uncle a cantankerous old dick. Don’t tell the older boys at school that Dungeons & Dragons is better than football. If you’re going to offer your seat on the tube to that pregnant lady, you’d better be damn sure she’s actually pregnant. Most people avoid these awkward situations by instinctively knowing how they’re expected to respond.

But there’s something wired into the genes of really hardcore geeks that makes them magnetised to uncomfortable silences. I still remember one of my first foot-in-mouth moments: at the age of eleven or so, at a friend’s birthday party at T.G.I Fridays, I thought it wise at the end of the meal to question whether the birthday boy’s mother was in a fit state to drive us home after that large glass of wine.

(Uncomfortable silence).

Why? What did I think was going to be the best outcome of that inquiry? “Chris, you’re right. Now that I think about it, we’d better take the bus. Phew, if it wasn’t for the cool head of this meddling child, we could have all been sitting in a flaming car wreck by now. Here’s a tenner for saving us all and showing wisdom beyond your years”?

Since then, my foot and my mouth have had an almost pornographic relationship. Everybody knows someone who’s prone to making the room cough nervously and stare at their shoes. For the sake of me wanting to make up my own acronym, let’s call them PFEs (Perpetual Foot Eaters). There are plenty of them about, and I guess the world would be a less funny place without them. But what is it about these otherwise lovely people that makes them the social equivalent of your moderately racist grandmother?

Having thought about it longer than anyone with a real job could afford to (read: about 14 seconds), I have come up with three main factors.

1. Many PFEs have a powerful sense of curiosity which completely overrides their sense of shame. This causes them to say things like: “Excuse me, are you a boy or a girl?”

2. Other PFEs have been born with an overactive zeal for fighting perceived injustices, which means they’ll carry on arguing a topic long after they’ve burst a blood vessel and all their friends have found a window to jump out of.

3. Some PFEs are just inconsiderate cock heads.

I’ve gotten a fair bit better at combating my PFE, and flare-ups are rare now. A recent incident reminded me that I’ll never be fully cured, however. I was having a meal at my parents’ house, and a family friend was recounting the wince-inducing story of a condition that led to him having a large chunk of flesh surgically removed from his back. As such, he had a sizable hole in his lower back for several long months of recovery. Succumbing to factor one, I unthinkingly opened my mouth: “So, did you ever feel a draft, like, inside you?”

(Uncomfortable silence).