What is it with sat-navs?

I have a love/hate relationship with my sat-nav; they are tremendously useful devices, but they are also massively frustrating.

I had a couple of run-ins with mine on the drive down to Bourg-Saint-Maurice to stay with Lucy and Sam.

We had to make a really early start (up at 2am and leave at 3am) to catch a 6.30am ferry from Dover to Calais, so I wasn't in the best of humours at that time of day. First problem was the M11, which signs on the A1 said was closed, so I had to choose an alternative route. I guess I could have stopped and reprogrammed the sat-nav, but I knew the next fastest route would be to carry on down the A1 and pick up the M25 at South Mimms.

I knew that, but the old sat-nav kept nagging me to turn off, do a U-turn, get myself towards the M11. I can't blame it for that, but we were past Biggleswade before the stupid thing gave up and got on the right track.

It was a miserable journey, raining steadily almost all the way. It has been a very wet January (the wettest on record in some parts of the UK). We got to the ferry port just before 6am and so were in plenty of time. Our ferry was also late due to the poor weather, so we need not have hurried quite so much.

I knew that me and the sat-nav would have a disagreement when we got into France. It is determined to take us to Bourg-Saint-Maurice via the Jura towards Geneva and then down into Annecy. That's a really long dog leg on the map and the roads are much slower.

Perversely, on the way back, the sat-nav takes you a different route (the route I'd like to go) which is via the Lyon ring round. That way, the journey takes eight-and-a-half hours compared to 10 hours via the Jura and Annecy. Basically, you can set the cruise control at 80mph as you leave Calais and switch it off at Chambery. I exaggerate, of course, but it is essentially two fast autoroutes to Lyon and then a fast run to Chambery, decent road to Albertville followed by mountain roads to Moutiers and Bourg. It's really easy and that's the way the sat-nav likes to come back.

So why, does it always want to go almost to the Swiss border and add hours to your outward journey? This time I was ready for it. As we got to Dijon, it said turn off; I kept going and it recalculated. No giving up, it wanted me off at the next exit with an even slower route nationale way back towards Geneva.

This man was not for turning, but it kept wanting me to turn for another couple of exits (perhaps 30 miles closer to Lyon). Then, all of a sudden, it saw the light, knocked 50 miles off the target and took me round the Lyon ring round.

We made really good time and got to Sam and Lucy's chalet at about 6pm. It was not quite dark and we'd also dodged some forecast snow, so a good run.