The first big mistake in the arts is to assume that because something is high-profile, highly publicised, and endorsed by a world-renowned organisation, it is going to be good.
The second big mistake is to assume that if it is not good, it is any the less enjoyable.
The head of the Royal Academy's summer exhibition, which opens next week, told me that some of the art on the walls will be "third rate". That is quite an admission, commendably frank, and not the greatest compliment to the artists of middle England submitting pictures. The other day he publicly admitted that he was "embarrassed" by some of it. But it is that third rate, embarrassing art that I shall be heading to first. It will tell me more about the real state of art in Britain than the Royal Academicians' work hanging in the next room. It will be fun, and I might disagree with the establishment view, and like it.
Likewise, at the Venice Biennale which opened this week, the column inches are given to the striking, cutting edge work of Britain's Mike Nelson, Karla Black, Anish Kapoor, and other worthies, round the world. But the real joy is taking a vaporetto to see the truly execrable.
Pride of place at the Biennale, bang in the middle of the Biennale curator's own pavilion, is the work of Swiss-born American Bruno Jakob. He specialises in "invisible paintings", blank canvases made with water, steam and mental energy. We are told that "the viewer must conspire in the process of creation and be willing to believe, as the artist does, that a blank space is not an empty space".
I set my imagination to work and my imagination kept telling me it was money for old rope. But I will tell my imagination to behave.
Blank canvases are all the rage this year in Venice. One "artwork" from Azerbaijan involved four poets reciting poetry for 88 hours on to white matting; the white matting "absorbs the poetry" and the four poets walk very, very slowly round Venice wearing the matting and spreading the invisible poetry. It's a living.
Not that Biennale art is always more comprehensible when you can see it. Step up the Frog King from Hong Kong, a man dressed like a London pearly king who approaches you and announces: "I am the Frog King from Hong Kong," and throw a bunch of papers up in the air. A different bunch every few yards. Litter as art. And not even recycled.
And yet I feel I shall remember the Frog King and the Azerbaijanis moving at a snail's pace in the Emperor's new matting, and the invisible paintings of Bruno Jakob as much as I will remember the acclaimed contemporary art at the Biennale.
The one great virtue of truly bad art, which great art does not possess, is that it can make you laugh.
A new way to part us from our money
Few things about attending an arts event annoy people more than booking fees, a point I have made many times. But now there seems to be a new way of getting audiences to part with their money when they buy a ticket. I see that the Barbican Centre, which is quite generously funded by the City of London, not only charges a £3.50 booking fee on transactions, it has started asking for "voluntary contributions" of £3 on top of that to go towards its outreach work.
What I do find a little odd is that if you book tickets online for the Barbican you are not simply asked for this voluntary contribution, you are charged it there and then and have to remember to "opt out" of the so-called "voluntary" charge. That, as I say, is odd. Is it also a bit unethical?
Can't count? Nor can mathematicians
One of the highlights of the Hay festival was Marcus du Sautoy, professor of mathematics at Oxford and a natural-born performer as well as writer on the subject. After his main talk at the festival last weekend he gave a more intimate chat to a much smaller audience which I attended. He used the occasion to demonstrate how maths can be useful in games. In Monopoly, he said, it's always worth remembering that the most common throw of the dice is seven as there are the most permutations of two dice that can come up with seven.
For example, he said, there was four and two or five and one. He paused and seemed to wonder why he wasn't coming up with more examples. A bold lady near the front took it upon herself to point out that these numbers were resulting in six not seven. "Mathematicians can't count," he said with uncharacteristic sheepishness.
He shouldn't feel upset. It was the highlight of that festival for me. I've never been great at the counting lark, and now I feel in exalted company.