This comes as no surprise to anyone who has seen Simon stomping around The Guardian offices (where he is film editor) in his socks, a cigarette behind the ear, swearing like a Tourette's sufferer; or standing with one foot on a chair, brandishing a piece of paper his colleagues are desperately searching for, holding forth about Ken Loach.
When I read Out of It, an account of when he nearly died from a rare, undiagnosed childhood illness, I had no previous knowledge of his story and at once I knew where his very individual (some would say twisted) take on life comes from.
He grew up in Broughton Park, a middle-class Jewish suburb of Manchester. His family were mainly medics on his mother's side and business people on his father's. He was a bright schoolboy who loved pop music, until he developed a raging headache and took to a noiseless, darkened room, losing all interest in life and half his body weight.
Out of It describes three harrowing years, from nine to 12, when Hattenstone had encephalitis, a raging infection of his brain that probably developed from something as mundane as a grazed knee. Doctors dismissed his condition as a cold, flu and then, when he didn't recover, as malingering and, eventually, as mental illness.
The book's passionate tone is shocking, even more so for those who know the writer as so laid-back to be almost comatose. "I was thinking quicker than I could type - it was like a haemorrhage, I couldn't keep pace with my thoughts," he says. "I wanted it to sound like a kid writing it, and so it was rushed and angry."
The source of the anger was that Hattenstone was in intense pain and wasn't believed; what made it worse was that the one who most vociferously argued it was nothing serious, the family GP, was also Hattenstone's father's best friend.
For a man normally fearless in his opinions, Hattenstone chooses his words carefully about his father; he clearly doesn't want to give offence to an old, sick man whom he has forgiven for initially believing his friend rather than his son. "My dad was caught in the middle. He was a typical man of his generation, where they spent more time with their friends than their family and where they always trusted their friends - particularly professionals.
"My dad was caught between his ignorance of medical matters and his best friend. In the end he made the right decision, which was to tell his friend to fuck off. But it was a difficult decision."
One of the most poignant passages in the book is about Hattenstone's recovery, which began after a bout of pneumonia that the doctors were able to diagnose. "I really got to know my dad then, because we had been quite distant, as many sons are from their fathers. Our relationship was probably saved when he realised it was pneumonia and got me off to hospital promptly. I think he was relieved to have spotted it because it sort of gave him a validity. After that, when I started listening to music again, he took time off work to be with me and we would listen to Pink Floyd together in the afternoon lying in bed."
Hattenstone is still very close to his mother, who never wavered in her belief that Simon was very sick. Out of It is dedicated to her and, at times, reads like a love letter to her. "It's almost like being the same person," Hattenstone says. She was suspected of suffering from Munchhausen's by proxy, a syndrome which makes people harm those they love in order to get attention. "They were horrendous to her. My mum was very bright and a non-mollycoddling type of mother, but one doctor suggested she see a psychiatrist. He tried to split up the family - he used to phone my dad and say she was neurotic."
While he is guarded in his comments about his father, Hattenstone speaks freely of the betrayal he felt by those members of his family who refused to believe that this sick child was for real. "They would refuse to come and see me for the year or so that I had an undiagnosed illness. It was only when I caught pneumonia they would see me, because it was a "real" illness. They were complete shits."
The book does seem to explain Hattenstone's character. He admits he lost out on the civilising, or at least socialising, years, where we learn that fart jokes are all very well but not in certain company. Easily bored, Hattenstone likes assuming personae for his own, if not others', entertainment. One of these is a salacious sexual harasser - "but mainly to men". More than one woman has failed to see the joke, but who could accuse this overgrown schoolboy of anything more than being somewhat socially inept?
Now 35 and the father of two small daughters, and having rejected his Jewish faith during his illness, Hattenstone lives with a Jewish woman. "Funny how I've ended up with one," he says. His partner, Diane, is obsessively tidy, while Simon's untidiness is legendary - for her, it must be like living with three children.
Hattenstone describes himself as a manic depressive, which he thinks comes from the illness. But while life may depress him, death does not. "It's too easy to say I'm not afraid of death, because 20 years ago I nearly died or should have died, but illness in adulthood is very different in its impact. It's not that I am self-destructive but I'm just not that bothered about conserving myself. For a long time I wondered what's worth conserving anyway. I don't think it now but I used to carry around in my head the quote `The most motivating thing in life is the fact that if things get too bad you could kill yourself'."
Writing the book has laid some demons to rest. "As an adult I'm not so angry about the illness because I believe it changed my life for the better. I may not particularly like myself now but I prefer myself to the person I would have been. My mum tells me I was quite nice as a boy but I always think of myself as a wanker." Which is probably true; one of the many self-deprecating stories in the book is how Simon would not lend his felt- tips to a classmate because he didn't think the boy was clever enough to deserve them. The image is so far removed from the Simon Hattenstone of today that it is almost surreal.
But the defining image of the book is the incomprehensible stupidity of the medical profession. How does he feel about doctors now? "Hate them - I always argue with them. I get so angry at the way they use their knowledge, or what they think is their knowledge, to undermine you." And what does he do now if he gets a headache? "I take an aspirin."
`Out Of It' is published tomorrow by Sceptre at pounds 12.99
You Ask The
Next Week: Melvyn Bragg
We hope to have answers to questions for Bob Geldof tomorrow. Meanwhile, please send any questions you would like to put to broadcaster and author Melvyn Bragg to: You Ask The Questions, Features Dept, The Independent, 1 Canada Square, Canary Wharf, London, E14 5DL; by fax on 0171-293 2182; or e-mail them to: your questions@ independent.co.uk by lunch time on Friday, 18 September.