Mines takes me the wrong way/play 9 out of 10 times. but eventually get you there after many pointless journeys. it also likes to try and get you to do U turns on the motorway etc. Technologie at its best
What brand do you have? Perhaps we should write a mini review each and see what brands we should avoid. I've had a few where my satnav has been a douche about things, especially when it asks to do U turns, I turn that off as it specifically asks to do it in the most awkward situations.
Mines a Garmin Nuvi 255w, I've had it for about 2 years now and it's map is out of date and I'm starting to encounter problems in some areas however I usually rely on the satnav for a general sense of direction rather than absolute, a more accurate speed reading and an distance/time to destination.