A.N. This was born from ACD!Lestrade resolutely (let me pass this adjective) having no first name, just an initial (G), and BBC's choice to name him Greg. As for the rest, it's headcanon of mine. As such, nothing particularly original, I fear...
Betaed by the wonderful, long-suffering Ennui Enigma (thank her!). Of course, lasting errors are mine.
Disclaimer: I'm not sure I need it in this particular part of the Sherlockian fandom...but I clearly own nothing but my speculations.
On first names and their bearings
It was after a minor case in November 1886 that my acquaintance with Detective Inspector Lestrade became more of a friendship. Of course, since that first case I followed Holmes in, back in 1881; I had met him many times. Until then our relationship was mostly comprised of shared looks of understanding and patience when we trotted behind Holmes. My friend can be perfectly unbearable just before becoming fascinatingly brilliant. On this particular occasion, the guilty man was especially feisty, and Lestrade had found himself in need of my own brand of professional help.
Grateful, he invited me to share a pint when we both had time. I accepted. Before I knew it, our pint sharing had become a habit. (Privately speaking, I owe to Lestrade my survival through that nightmarish period known as the Hiatus, especially after dear Mary passed.)
That first time we met informally saw many confessions. Lestrade reproached me amiably for my tenacity. Apparently, there'd been a betting pool at the Yard about how long I'd stand sharing rooms with Holmes. Lestrade had (feeling daring) overestimated and put his money on the ten-day mark. He had not lost though: the bet had been called off because even the more 'insane' of them (Hopkins, with his puppy crush on Holmes) had not believed I could last more than three months.
I admitted that if I'd had a clear knowledge of what awaited me, I wouldn't have bet past the first week myself, prompting a raucous laughter. Thank God Stamford's warnings and Holmes' self-presentation were sketchy, at best, about what was to come. Being scared off this cohabitation would have been an unimaginable loss.
Suddenly I realized something and just had to ask, "By the way, Lestrade, what's your first name?".
"Now you're keen on first names? That's not like you, doctor!" he joked back.
"Come on, Lestrade, there's no need to be so formal while drinking together. I promise I won't tease, whatever it is. I live with Sherlock Holmes, and I never once remarked on that," I exhorted with a grin.
"You know, he's so masterful all the time I never even noticed how odd such a name is. It must have been hell being a teenager. Probably what sharpened that tongue of his," Lestrade replied, suddenly pensive.
"And this is a really poor attempt at redirecting conversation, inspector. If you behave like a reticent witness I'll have to assume the worst. I know it starts with 'G'. Galahad?" I guessed.
"Your imagination is vicious, doctor. With such a name I'd lie hidden in a mole-hill somewhere. No, just plain, old, Gregory. And I'd appreciate if you kept it to yourself," he confessed.
"Of course I will, but why? What's the black secret behind it?" I questioned, honestly curious, leaning a bit towards him.
"Tobias – currently detective inspector Gregson – and I started working about at the same time, and were often paired together to go on patrols and whatnot. Really doctor, you must have seen the rivalry between us – more than a simple acquaintance can explain," the inspector said.
I was used to Holmes belittling my intellect, but I almost sneered back at this jab. Holmes was Holmes, and the liberties he took were plentiful and well deserved. This man had no such right. Only my eagerness to know kept my mouth firmly shut.
"And that was a right headache. Every goddamn time someone called 'Greg' we'd both turn our heads. He expected the call to end with that extra syllable of his last name, and I thought someone was being friendly with me. We were right, each about half the time. This 'turning together' act made us look like bloody twins. The last straw was when a colleague referred to us as the 'Greg & Son' team. Neither of us was particularly amused, I'll tell you that. We let him know we weren't some sort of comedic duo (separately, for once; me first) and after that, we decided that we needed to stop behaving like idiots. Since then, on the job I answer only when respectfully addressed by my last name. I have to say that was a big nudge to further my career, but made me look like a stuck up bastard for a while. Probably I'm still reputed so. Of course, my career pushed Gregson to work on his. He's more educated than me (or so he says), so the sod expected he'd 'naturally' get higher than me. Well, he hasn't managed it yet," Lestrade snorted, starting his tale awkwardly but definitely smug in the end.
"Good for you then, isn't it? With any other name perhaps you wouldn't have been half as quick in your promotions. You should really thank your parents, Greg. Uh, sorry. Can I call you Greg off work?" I queried. Any bitterness I had held was dissolved by the comic mental image forever engraved in my brain.
"Yeah, of course. It's refreshing, actually. I just don't want it to come to the ears of our young ones. Last thing I need is a repeat of that awful joke, or some sort of modern remake of it. You know, John, you owe me an answer now," he agreed, with a grimace morphing into a smile.
"Ask away," I replied with a shrug.
"What's the matter with you and Holmes? I know he's not what you'd define as normal, but you've been flatmates for years now. One would think you should be past last name basis since a long time ago. You don't exactly tiptoe around each other," Lestrade – Greg – questioned, with a fond smile. Well, 'not tiptoeing around each other' was one way to put it. 'Being frequently overwhelmed and very happy about it' was another. I suppose being overly polite didn't fit with the rest of the image we portrayed.
"It's simple, really," I explained. "At the start of our cohabitation, Holmes informed me in no uncertain terms that he didn't like his Christian name at all, and he'd be much obliged if I could refrain from using it. I acquiesced, obviously, on the condition that he'd extend the same courtesy to me. There was no conceivable reason to give people the false impression I was some sort of subordinate of his, after all. He agreed promptly. Honestly, I thought with time the excess of formality would irritate him and we'd move to a more normal system. I sorely underestimated both his contempt for normalcy as a rule and his stubbornness. Since my own tenacity is a worthy match to his, we persevered like that...and by now, to call him anything else would feel nothing but wrong," I admitted honestly, taking a sip to swallow the truths that were not mine to reveal.
"You'd startle us too, if you decided to suddenly change habit now," Greg acknowledged with a chuckle.
We parted shortly after, and my mind was still on first names and their unexpected bearings.
Like how Sherlock hates his name not because it's weird, but because it's wrong. Apparently it means 'fair-haired', which is about as far from truth as an adjective can get. With my friend's obsession for details (significant ones, at least; but he can't delete his own name, can he?) such imprecision grates on his nerves in a way nobody will probably understand.
Or how I've started to hate my own (a good, honest name; a solid name, I used to think) since I live with him. Because the only times it leaves his lips are when he's under the influence of his infernal drugs.I have no idea why Holmes' drug-addled conscience refuses to utter 'Watson'. I know I'd live quite content to never hear him call me 'John' anymore. If renouncing my first name forever – from anybody – would help, I'd do it in a heartbeat. But I realize that such a vow is too trivial for any self-respecting god to even consider it. There will be no saving my friend from himself in exchange for such a menial sacrifice as that of my given Christian name.
Now, without my Mary, the chances of finding myself in need of a name to christen a child with are next to zero (I won't say zero because two things Holmes taught me firmly are that improbable is not impossible and that life is stranger than you can imagine). However, if you, dear reader, are in this happy circumstance, take heed. Keep in mind that words – and names all the more – are powerful.