Have a few drinks and drive home at your peril. Many people in Hong Kong do not consider drink-driving a serious offence, but when John Hoskison did it, he was given 18 months in three of the most dangerous prisons in Britain to think about his mistake.
After reading this account of his ordeal, one suspects he is unlikely to make the same mistake again.
Prisons are not the same the world over. When drug smuggler Billy Hayes, whose case was made famous by the film Midnight Express, found himself in a stinking hole in Turkey, no doubt he could but dream of being behind bars in his native United States.
But whether one ends up in a Turkish hell-hole, or among the 8,500 or so inmates in Hong Kong currently protesting about the excessive violence of the prison officers, or the 60,000-odd in Britain as Hoskison did, the shock and loss can be devastating.
All the more so when, as a non-violent first offender, Hoskison could have expected a reasonably cushy stint in an open prison. Bureaucracy condemned him to harsher treatment.
Had he not mown down and killed a cyclist, he would have spent his months - he served half of his three-year sentence - from October 1995 on the golf course, earning his crust as a professional golfer.