The first thing I notice about David Shrigley is his balls. Twelve thousand, one hundred and sixty six of them, to be precise, lined up neatly over almost every available inch of the gallery walls. Walking around this room of dazzling yellow is a surprisingly psychedelic experience – the bright lights and recurring patterns play havoc with your brain. “It’s ended up looking like a piece of op-art,” says Shrigley, who talks almost as if he had no hand in it. “I wasn’t anticipating that.” The work won’t stay like this. The idea is that for the next few weeks people can wander in off the street and trade these fresh tennis balls for worn-out ones of their own. It reminds me a little of Roelof Louw’s 1967 sculpture Soul City (Pyramid of Oranges), only instead of the work gradually dwindling as visitors interact with it, this will evolve into a grubbier form: a slow, ugly decay. Shrigley says that ideas around trade, currency and even his dog Inca’s (lack of) ball retrieving skills served as inspiration for the work – but really I think he just likes the idea of people doing something weird in the middle of Mayfair. Not knowing exactly what’s going to happen is, he admits, one of the main thrills. The work arose from a question many of us have asked ourselves over lockdown: “Why, exactly, am I doing this?” Shrigley took the time to reevaluate his career and realised there were things he didn’t want to do any more. “I just didn’t want to do another presentation of works on paper,” he says, of the strange, amusing and unsettling drawings that made his name. “I was a bit jaded about making the same exhibition over and over again.” And so Shrigley started creating more conceptual works. In the gallery space across the road from the tennis balls exhibition is a digital wall clock he made, in which the bright red LED digits are blurred, making it almost impossible to read. Shrigley is 53 now, but a few years ago he was in a taxi when he noticed the car’s clock was out of focus. It turned out he needed glasses. “I don’t quite know why I’ve made this,” he says. “It was quite expensive and I don’t know exactly what to do with it.” He gazes at it as if it’s some work by another artist he doesn’t fully understand and tells me how it’s a complete departure from his usual style. I’m not so sure. Feeling your eyesight fail as a clock ticks down another minute closer to death doesn’t feel entirely un-Shrigley like to me. We retire to some sofas. Shrigley speaks quietly, in a soothing monotone that rarely pauses, and you have to listen attentively to tell what he’s actually passionate about and what is just tangential rambling (the inner workings of my Dictaphone, for example). He’s adamant that he still loves drawing: “It’s my life’s project, somehow,” he says. “The inquiry continues and it will never end until I’m gone.” But he will occasionally say things that suggest he finds the process, if not frustrating, then certainly a little baffling. “I will make 100 works on paper with the intention that no more than half are any good,” he says. “And there are probably four where you’re like: ‘This is basically fantastic! This is me demonstrating my area of expertise and all the other 96 are just attempts to do this.’ And do they sell? Do they fuck. You look through the inventory going: ‘Nobody bought that? Nobody bought that? Well, what did they buy?’ And it’s a picture of a cat or something.” He laughs. “I’ve realised my tastes are very peculiar relative to the rest of the world. I see genius and other people see rubbish. I see rubbish and they see genius.” These days he lets the gallery choose which works to exhibit. For Shrigley the drawings that he likes best are the ones that surprise or confuse him. “Where I think ‘It’s kind of funny, but I don’t know what it means … so I’ll just put it out there and figure it out.” It’s the same reason he enjoys his more interactive work – inviting people to draw a giant urinating sculpture as part of his Turner prize show, opening pop-up tattoo parlours so people can have his doodles inked on to them, or inventing a bunch of strangely shaped instruments – such as a one-stringed electric guitar – and getting musicians to play them. One of his musical heroes, Sonic Youth’s Lee Ranaldo, recruited a bunch of avant garde musicians and terrorised a New York restaurant with Shrigley’s instruments. What did it sound like? “A noisy racket,” he says. Shrigley was born in Macclesfield but grew up in Oadby near Leicester. His main interaction with art as a kid was through record sleeves (the Fall’s Live at the Witch Trials was a favourite, long before he heard it). But it was a trip to Tate Britain with his dad in 1982 that really sparked his interest: Jean Tinguely’s kinetic constructions led him to Dada – the absurdist art movement that sprung up in Zurich during the first world war – which he still believes is the most important moment in art history. “Thinking of art as being in opposition to everything,” he says. Unsurprisingly, this obsession led him to being a “smart-arse” student by the time he’d arrived at Glasgow School of Art. His tutors didn’t always share the same outsider viewpoint. Was he disappointed with a 2:2 after his final show? “I was mortified, yeah,” he says, deader than deadpan. “I felt like I deserved a 2:1.” He says the art school put a lot of emphasis on traditional craft, which reminds me that the Guardian once said Shrigley “would win few prizes for drawing, and even fewer for his handwriting” – does he agree with that? “Well it depends what the competition would be,” he says, laughing. “Put it this way: when I was six, I was the best at art in my class. By the time I graduated from art school, I was close to the worst. It’s just not really important, I suppose. I make the drawings that I make through a desire to present ideas in as economic a fashion as I can.” He went through this same journey of understanding with René Magritte: he considered the Belgian surrealist a master painter at 14, but by the time he got to art school and learned to draw himself he realised he wasn’t actually all that. “And then by the time I graduated I understood that none of that mattered too much anyway,” he says. “For me, it was all about Ceci n’est pas une pipe. That’s such an important statement, an illustration of the slippage between language and image.” You can certainly see the link between that work and what Shrigley does. “Whereas I have no interest at all in someone like Salvador Dalí,” he says. “Well, not as an artist. If he was presenting Bake Off then I’d definitely watch that.” Shrigley left art school feeling as if he had no saleable skills. But then he got a job at an agency – “they said ‘we like the way you think’” – and struck gold with his simple yet inimitable combinations of drawings and text featuring freaky figures and twisted thoughts. “I play in my play pen. I am very happy,” reads the text next to a caged stick man. “I don’t know why I did it,” is the caption to a man aiming a catapult at a hairy beast’s bum. His work, which used to feature weekly in the Guardian’s Weekend magazine, has ended up on tea-towels, salt and pepper pots (labelled “cocaine” and “heroin”) and greetings cards (“We will be glad to attend your wedding,” says one message, running down the full length of a cock and balls). I wonder if the recent political turmoil has had an effect on his drawings, and he says that inevitably it has. He’s noticed they have a lot more swearing in them. “But then again, less bloodshed.” People read their own messages into them regardless. “You think you’re making a work about the climate crisis and then it becomes about the pandemic, because that’s what everyone’s thinking about. Or everything you make becomes about Brexit.” He tells me about a work he’s making at the moment which is harder to misread: “I’ve acquired 5,000 copies of Dan Brown’s The Da Vinci Code, and I’m pulping them all,” he says, with a hint of mischief. “Then I’m making paper with it and, on that paper, I’m reprinting an edition of Nineteen Eighty-Four by George Orwell.” He laughs. “I can do it because nobody wants to buy The Da Vinci Code any more – they just want to deposit it. So that for me is a project about: ‘Wake up! We are sleepwalking into a totalitarian regime!’” Suddenly, his enthusiasm dims: “Making that artwork feels like a very impotent gesture somehow,” he decides. Which brings us to another lockdown decision he made: selling his house in Brighton and setting up Sidmouth School of Art, a mental health and wellbeing charity in Devon. At the moment the four people behind the project are applying for charitable status and have spoken to a local GP practice about the idea of referring people to them. The thought of being prescribed an art session with Shrigley paints an image as surreal as some of his own works. Butthe artist reasons: “If I can make an art project that is helping people with mental health problems then is that more helpful than making a funny drawing about the mental health crisis?” He’s not without experience: back in Glasgow, where he lived for 27 years before moving to Brighton in 2015, he participated in community education for five years. He found working with elderly people, mentally disabled people and prisoners rewarding – although other jobs were more challenging. “Personality wise, I’m not so good at dealing with hostile Glaswegian teenagers. With weapons. Who don’t want to do the papier-mache,” he says, before putting on a fantastic Scottish accent: “Ah dinnae wantae paint a picture ye prick!” I suspect Shrigley himself will be a beneficiary of the charity too. He says he’s spent his career feeling “not like a fraud, but … a bit selfish, like I’m just pleasing myself and enjoying my life far too much.” Recently he’s been reading about people who have overcome chronic pain through their artistic endeavours. “This one woman was really suffering with an arthritic condition, she was basically incapacitated. Then she joined a choir and the pain went. The doctors don’t know how it works, they just told her to keep doing it.” Once more he sounds utterly astounded by this endlessly confusing, utterly unknowable thing he’s devoted his life to. “It was just so exciting to find out that art is … actually good for people.” David Shrigley: Mayfair Tennis Ball Exchange is at Stephen Friedman Gallery, London, until 8 January.