Satellite navigation, GPS - or whatever else you want to call it - has a wobbly side. Indeed, sometimes you wonder if the in-car 'sat-nav' unit meant to be smoothly leading you to your destination has been drinking or taking tips on disruption from HAL, the rogue computer in 2001: A Space Odyssey. Take the tale of a San Francisco surveillance-camera expert who recalled how his GPS unit once told him to do a U-turn on a freeway, without giving advice on how to avoid oncoming traffic. Happily, he retained enough autonomy to disobey. However, recently, a story emerged of a German who, 'just obeying orders' given by his sat-nav, headed straight onto a tramline in Bremen where he became stuck. No one was hurt, but about a dozen trams were delayed while authorities tried to tow his car away amid the ensuing chaos. Such horror stories prove sat-nav is by no means oracular - a problematic fact if you tend to be gullible enough to go with the flow. And you probably are: computers, especially models endowed with the ability to talk in a cool, patronising voice, have a men-in-lab-coats aura. They smack of Milgram's experiment, the 1967 test conducted by Yale University social psychologist Stanley Milgram that showed we will torture members of our own species provided we get the green light from an authority figure. Doubtless, then, the typical driver would comply with a sat-nav edict saying: 'Keep straight on until you arrive at the cliff then continue ...' Another minus is its supposed ability to undermine your thinking capability and make you apathetic. This is a familiar allegation routinely levelled at computer games. But, according to The Times newspaper in Britain, if you care about personal development, maps are where it's at. The typical map 'sharpens our hunter instincts and sense of discovery', the paper claims. That depends if you can read them. I can't - I must have some kind of flawed chromosome. Another reason for not messing with maps is that, despite generally being thin when folded, they still hog space, which seems remiss in this age of the Zen decorating aesthetic. Also, they weather and get grimy. Sooner or later, unless you treat them like the Dead Sea Scrolls, they shred like your nerves during a navigational altercation with your other half. If you are lucky enough to be alone during a mystified moment, you still need to deal with the feelings of inadequacy caused by the realisation you're on the wrong road. Before the days of sat-nav, I would have killed to hear a god-like guiding voice say something like: 'Stop driving west, you moron. Hang a left.' Instead, I would bumble on into some dangerous fringe suburb where ducking into a shop could result in my CD player being reduced to three wires sticking out from the dashboard. Thieves now target sat-nav systems, which along with laptops must rank as some of the most 'nickable' items around. Even so, sat-nav is more a blessing than a curse because it allows you to focus on the cutthroat business of driving. If you feel you need to sharpen your hunting skills, wait until you get home to your favourite computer game. Meanwhile, remember you have the power to override the voice of reason. Unlike HAL, your guide is not your master. Not yet anyway - give it time.