The meal deal: Richard Serra at David Zwirner, Jim Shaw at Gagosian, Barbara Kruger at Sprüth Magers

For the past few weeks, the art world has been doing what it does best: bouncing around from city to city. First, it was Venice for the Biennale, then Berlin for gallery weekend, and last week it was New York for Frieze art fair. Meanwhile, I’ve been in London. I guess my tickets got lost in the post. I know I shouldn’t say so, but I don’t mind skipping these events. I’ve never found fairs and parties a good time to actually see the art. And that’s what everyone’s there for… right? Thankfully, Plaster’s party correspondents were on the ground, on the guest list, and somehow managed to file their Venice and New York reports on deadline from the free bars.

This is the last show Richard Serra worked on while alive, and the first show to open following his death. That’s not the only reason to see it, you should go simply because it’s beautiful. Each of the six drawings is made of sheets of mulberry paper coated with greasy smears of oil stick that give a uniform blackness only broken up by the surface texture; cratered, flaking, like the pitted rusted hull of a ship or the burnt bark of a tree. There’s the same interest in mass, voids, scale and texture in these works as in his sculptures. They even hang like his sculptures stand; uneven, tilted, yet balanced. The gaps between the black sheets reveal the white support, which shines through like sunlight between metal plates. When you put it in words or in photos it all seems so simple. But these are difficult works, they’re confrontational, direct, and unforgiving. No matter how long you spend in front of them, you don’t get any closer to one answer. I actually dropped by twice, and I’ll be going back again.

Jim Shaw doesn’t have a style, rather a source (American popular culture) and a way of treating these images (with irreverence). You see this best in his new works; three painted collages created from 1950s Trans World Airlines adverts and cold war political cartoons about the United States’ burden as peacekeeper of the world. As adverts and propaganda, these images had the power to persuade, promise and deceive – peace, prosperity, and the world at your feet – through time and Shaw’s translation from print to paint, they’ve lost all of that. But I was distracted by the two older works; a dancer in a graveyard and a black and white painting of Trump and Melania descending into hell. In style and subject, neither of these works fitted in. There’s not much to go on, just those five works. Really it’s an aperitivo for anyone landing in London and catching the Eurostar to Antwerp, where there’s a much larger exhibition at the Museum of Contemporary Art. Like an aperitivo, it might not be to everyone’s taste, but it gets you hungry for more.

I didn’t think much of Barbara Krugers’ Serpentine exhibition, but I wanted to give her another chance. I’m glad I did. The simplicity, scale and back-to-basics approach makes this a much better show. Downstairs, there’s a new series of optical illusions on canvas and vinyl. The short phrases that you can only associate with Kruger seem to punch out of the walls. I watched several people become drawn in by the sculptural novelty and visibly disappointed by the flat reality. It got me thinking about all the other cheap tricks of modern life which promise so much and deliver so little: VR headsets, AI art and the empty sexual promises of spambots. Ironically, the illusions work much better on phone screens than IRL – much to think about. Upstairs, there’s a set of Kruger’s black and white ‘paste ups’. Between the two floors, you have the story of a consistent vision and continuing relevance. All without resorting to video essays.