My first name’s hyphenated: J— -P—. I hardly ever call myself by just the first half, though. The one place is in my handwritten signature, which is rarely seen and is such a scrawl that nobody would decipher it when a block-capital alternative is nearby. And any work e-mail signatures have my whole name, and are usually preceded by “Cheers, J-P” or “Best regards, J-P”.
So why do people insist on calling me J—? My parents saddled me with this mouthfilling moniker, so I’ve had it pretty much since birth (with a brief pre-teen shortening: short-lived, haha). My schoolfriends eventually reduced it to its initials and pinned that on me pretty much forever. Nobody who knows me calls me J— any more, apart from a couple of recalcitrant college oddjob-men. You never see the name J— on its own in any correspondence from me, so why do it? Why on earth advertise that you don’t know me very well?
… That last bit was rhetorical, OK?