There is the kind of graffiti or street art that breaks out and goes on to bigger and better things. The Banksy works that are removed from their place of birth and sold for hundreds of thousands, for instance, or the murals on the West Bank wall.

What I’m infatuated with is the more discreet, local graffiti; spontaneous doodles found in unexpected places. The messages that can make visits to the loo a reading experience almost as pleasurable as sitting in a library scouring quirky book annotations: a scrawled observation that the design of a coat hook resembles a drunk octopus; the hidden confession of unrequited love; the country’s legislature taken to task via marker pen.

Even better are the dialogues. I have seen, on more than one occasion, questions posed about relationships that have been answered in separate handwriting: “Dump him!”, “Girl, you deserve better”. I love inspiring quotes, too – the sort that if posted to Instagram might cause me to eye-roll, but somehow, etched against the grain of a stall, speak to me.

A few weeks ago, on a weekend in which temperatures hit 29C, I saw a sign that had been changed from: “This road will be closed for temporary roadworks” to “for a temporary beach”. The idea made me smile. A road round the corner had been pedestrianised a couple of years back, while a bridge was being repaired, and it had naturally morphed from a rat-run into a space for neighbourly parties and kids’ play. The metal street sign peeling off a wall daubed with “fix me” also has a community spirit.

I enjoy spotting recurring graffiti. Far and wide across London, the words “Nat has herpes” are scribbled on various surfaces, from bus stops to subways. Nobody knows who Nat is, or whether she really does suffer from such a malady. It’s been mooted that one person could not have been responsible for all instances, and that it has become a copycat situation. The phrase never has the tinge of a sexist slur, rather the air of a friend taking the piss. Now it has been elevated to part of the urban fabric.

The corporate commissioned graffiti represents the worst of street art. But the witticisms, heartfelt sentences and subversive acts from fellow humans are a boon. My favourite from the past week? The person who had added in the female actors’ names on a film poster, when only the men in the image had billing. Thank you.