Garmin Nuvi 2595 Gives incorrect directions.

Units learn your driving habits and preferences. A lot depends on what you select as options and avoidances. Most here default to the fastest route and have very few avoidances checked. On my particular unit I have only dirt and seasonal closures selected as avoidances unless I am somewhere I don't want to pay a toll. As I have a EZ Pass, toll roads in my area are not as much an issue, but when in a non EZ Pass area, I normally add avoid tolls.

You need to remember, the unit only suggests a route and it is up to the driver to actually make a decision as to if they will follow the unit guidance. These units recalculate routes on the fly, so moving off the initial route will usually result in the route to your intended destination being recalculated from your current location.

I have a 2595 and have not experienced anything like you describe.

So, help us do some debugging by telling us what is checked when you do:

Settings > Navigation > Calculation mode

Settings > Navigation > Avoidances

Settings > Navigation > Custom Avoidances

Remember that "avoid toll roads" also includes toll bridges and the like. Did your preferred "avoid toll roads" route take you over a toll bridge by chance? If so the Nuvi would go to great lengths to avoid that bridge(s).

Also avoiding a toll road and selecting a Faster Time route could generate a very different route than an avoid toll road Shorter Distance selection.

This feature can cause all kinds of strange routing problems as well. It uses historical traffic data and the unit uses this information to set the route. Check the detour settings and turn off automatic re-route around traffic delays.

A Custom Avoidance can be a bit of a pain to set up, but it can be worth it. I returned, from Napannee, IN and had Avoid Tolls, so that I could avoid the Indiana Toll Road. The Blue Water Bridge has a $3 toll, so the GPS wanted to route me through Buffalo.

By setting the toll road as a custom avoidance, I could uncheck the Toll Road avoidance. That allowed me to use the Bluewater Bridge, but avoid the ITR. You can enable or disable any of the custom avoidances, once you've set them up, so you won't stuck with them all the time.

You usually only need to avoid certain toll roads, or sections of the road. By setting a blanket toll road avoidance, the gps will have to avoid "all" toll roads & bridges.

Good idea about using the Custom Avoidance feature!

I'm surprised your Nuvi would route you to Buffalo unless it was just to get you on I-90 Eastbound. There are lots of stories from folks attempting to get from the US to southern Ontario and Toronto with the Toll Road avoidance turned on and getting routed all the way past Lake Ontario to some spot along the St Lawrence River as all the bridges and Tunnels from Detroit east to at least, Ivy Lea, were tolled.

A couple of years ago I left New Orleans heading towards the Blue Ridge Parkway. I was on a four lane with a median road and the Garmin told me to take the next exit. I did that and ended up going through a small town, traffic lights and all just to go back onto the same highway I had left earlier.
This happened 3-4 more times and I just ignored the GPS directions.
My settings are for the fastest route, not shortest route!

Quite a few years back, my wife and did a driving tour around Zion Canyon, Bryce Canyon and North Rim Grand Canyon. We had a wonderful time. Driving from Bryce to North Rim, however, was kind of interesting. There is this HWY67, a straight shot from Jacob Lake to the North Rim, ~45 miles. I was using a Garmin 1390 that simply refused to use, no matter what I tried. It routed me through a serpentine route along the unpaved service roads.

I thought there might be something wrong with the conditions of HWY67. Good thing we stopped at Jacob Lake ranger station and checked. There was nothing wrong with HWY67. We just took 67, ignored the routing suggestions of the 1390. We had a smooth drive to the North Rim and enjoyed a very enjoyable and relaxing stay and one of the most spectacular scenery anywhere.

After my trip, I did a lengthy Web Chat with a very helpful and knowledgeable Garmin support. We could not figure out why. The best we could guess was there might be a built-in seasonal closure imposed on HWY67 that is out of sync.

I bought the device for the specific purpose of using it during a long expected vacation with the family in Saudi Arabia's seaside Eastern Region. The distance from the capital "Riyadh" is 400km and the road is simple and familiar "go straight ahead for the next 398km". The reason I was using the GPS however was that the cities I was visiting have perplexing entrances and exits and one wrong option can send you about 35km back to the highway.

To my shock, however, Garmin Nuvi 57LM kept telling me to take every wrong exit on the road. I am glad I had revised the route prior to the trip or other wise I would have never had my vacation on that day. I stopped at a gas station and reset a few options that I had made: same errors.

With the help of my wife, while driving, I finally removed the system from the car holder and placed plain old google which did a fantastic job throughout my holiday driving times.

When I was back home I thought of testing the device again within the city of Riyadh. I selected a post office on a service road where I needed to visit. all went very well except that just a few hundred meters from my destination the device told me to go on and take the exit to the main road. You can guess that I didn't!

Well 'wrong' is subjective, what you mean is not the one you were expecting. However what avoidances and routing settings did you have set on your nuvi? Which map were you using? These all affect the route that will be chosen by the nuvi.

If you can post some details of the route and which map then I can check out whether it's the nuvi really at fault or whether it's simply a setting issue that you didn't make.

That info has a great deal of how the Nuvi will map a route; you can always ask Nuvi to change the route