I thought I knew my right from my left...

Having the same problem with my C530 and always has had it. I would almost say it gets it wrong more than it gets it right. 2008 & 2009 maps.

I have had my C340 tell m eto turn right and the screen clearly shows a left hand turn so I can't say that has anything to do with house numbering. Not sure what the answer is but I try to always look at the screen before turning to make sure that Jill isn't "showing her blonde side"

I had a similar experience, showing a POI on the right when it was on the left.

Just this afternoon my wife and I were going to find a place for lunch. Told us "take Exit 8, Stay Right and keep left, and then right to X Rd." Jill said to turn left at the exit, but the route went right. We turned left, but no biggie the roads met again a couple of miles further toward the destination.

Telling me that a destination is on the left when it is really on the right is a common problem for me. Happens on both the built-in POIs and the POI factory POIs. It is hard for me to understand how this happens for built-in POI since they seem to be based on street addresses and the GPS should certainly know which side of the street is even and which is odd. But when it happens with POI factory POIs it is a matter of inaccurate GEO coding of the POI. Having done some geocoding I know how hard it is to get good data here, and most of my effort is in making sure that I don't accept a coordinate set that is out in the middle of nowhere or on a completely different street than the one that I'm trying to look up. If you don't know the area then it can be pretty hard to be sure that you have the POI positioned on the proper side of the street in some cases.

I've seen plenty of POIs here that tell me the destination is on the wrong side of the street. I generally don't even consider this important enough to notify the POI author about. While it would be nice if the data was as accurate as it can be, there comes a point where too much nit picking can be discouraging rather than have positive results.

When I read the subject title I first though that you were posting about a different problem that I have seen a few times (although very rarely): The GPS actually showing a right turn arrow on the route display but saying "Turn Left". I have no idea what causes this but it has happen for me. This is so hard to believe that I even took a screen shot the last time that it happened to me, the unretouched screen shot (converted to jpg from the original larger bmp) is here:
http://img132.imageshack.us/img132/8615/916f.jpg

I have also had a case where the routing was telling me to turn right, on roads that I take all of the time, when I knew that I wanted to turn left. I turned left and the GPS did it's "recalculating" thing and the rest of the route was fine, but I wonder where the GPS thought that it was going to take me and where I would have gone if I followed that "turn right" instruction. If gas was still cheap I might have even followed the instructions to see what the GPS was up too, but I can't afford that any longer.

Weird stuff happens and hopefully not often. A month ago, Jack told me to turn right at an intersection that clearly had a left turn lane and I really needed to turn left to get to the destination. While waiting for the light to change, I looked at the route he plotted and if I had turned right, he was going to have me make a u-turn at the next block and then come back through that same intersection!

A couple of days later I was in the same area, so I asked Jack to take me to that same place and this time he correctly told me to turn left.

If you could recreate the scenario, it's likely there's a bug in the map or program, but when stuff like this happens, ya gotta wonder what meds Jack has been taking!

Jack got a little AC in his DC?

I saved by home's original waypoint on a Streetpilot 3 about 6 years ago and have moved it through about 10 generations of GPS receivers as part of an ever growing list of waypoints.

With the release of CNNT 2009 my home seems to have changed sides of the street as far as my Nuvi 780 is concerned - the device tells me my house is on the left as I approach, rather than on the right.

The implication is thet the GPS receiver or the mapping has changed registration.

Can't quite tell which because I have two current navigators and both run CNNT 2009 - the Zumo says I'm on the right, the Nuvi says I'm on the left (wrong), but the Nuvi USED to say I was on the right when it ran the original CNNT 2008

So there's something a bit strange in that;

If it was mapping, then the Nuvi is right - when I went from 2008 to 2009 I changed sides on the street.

Yet the Zumo 660, which was delivered with the same CNNT 2009 generation of maps says my home is on the right (correct).

It's all very curious.

As to sometimes strange routes? Every navigator I've ever owned has at one point or another planned a route that involved turning the wrong way and then making a U-Turn. Don't know why, but looking at the map rather than blindly listening to the device has saved me some mileage.