It's not fair to generalise about the differences between north and south London but true Londoners will always specify a favourite side of the river.
Last night on the Northern Line (one of the few things Islington and Lambeth have in common) my own belief in southern superiority was reinforced by other passengers of the kind I've only ever seen or met in an N postcode.
A white, bald and drunk Scottish man with a tattoo on his ear embarked at Old Street, played a Rangers anthem out loud through his mobile phone and sung along with it in ragged fashion.
Playing music through a mobile on public transport is usually the preserve of boisterous bus-riding teens into urban music, but the Scotsman's differing genre interests and transport method made no difference. It was annoying to hear a Caledonian football song played through tinny speakers on the tube. But is it best to ignore a Saturday night pisshead's foible?
Rangers fan and his pal were about to leave the tube at Camden Town when I decided to speak up, although not in the manner of a Grumpy Old Men contributor.
"You've got better music than that in Glasgow, man."
"[Indecipherable Glasgae muttering] You must be one of them."
After a second to think about the religious and sexual connotations of being described as "one of them" by a Rangers fan, I replied: "One of them? What, person with musical taste?"
Soon another man stepped into the carriage with a tattooed face but at least he declined to inflict his dubious musical and sporting taste on the rest of the weary Underground users in the carriage.
With a face covered in ink which doesn't rub off, though, there is no need to make an audible statement. You've already shown the world exactly how you refuse to kowtow to accepted decorative body norms.
Or rather, illustrated that the only jobs you'll ever be fit for are boxer, tattoo artist or thrash metal band roadie.