Shortly after our Startup Tour began this summer, Heath Ledger died. No, not Heath Ledger the actor, who died a couple years ago of an accidental drug overdose — Heath Ledger, my four year-old Garmin NUVI GPS who spoke with an Australian accent. My Heath had been going quietly insane for some time. This is his story.

It seemed like nothing serious at first — a forgotten route, a missed turn, some confusion about where home was. Heath was still Heath but maybe a step slower than in his youth. Then he started routing us gratuitously, sending us to places we didn’t want to go. After that came the endless loops, which with a driver like me sometimes aren’t noticed until the third lap. Heath, in advanced age, was experiencing dementia. It’s not supposed to work that way (this is digital of course — perfect) but it was.

Drive across America visiting little companies in little cities and your GPS becomes you best friend. Only this best friend had forgotten my name.

Time for a new Heath.

Bought on sale for $134 at Best Buy somewhere in Illinois, my new Heath is a NUVI 255 with a bigger screen, faster processor, and overall badder attitude than the Heath he replaced. After 10,000 miles and almost 200 hours of driving together, I know this new Heath very well. And I don’t always trust him.

It’s like playing a video game so many times to where you come to understand the flow of the game and how it functions on a level maybe even the programmers didn’t consciously know or intend. That’s how I understand this new Heath, my driving partner and sometime enemy. He doesn’t lose his mind like the Heath he replaced, but he doesn’t always like me, either.

Indulge me while I explain my understanding of Heath’s routing algorithm.

To my new Heath, faster means faster and shorter means shorter no matter how stupid the route turns out to be in human terms. So if you tell Heath you want the shortest route and there are many possible choices but one is 40 feet shorter than the others despite having 60 percent more turns and stops, Heath will save the 40 feet. Same for faster, even if faster requires cutting a corner by taking a one-lane dirt road in your 34-foot RV. The speed limit in his database says 65, after all, even if you can only go 30.

Heath has done both of these things to me.

One of the joys of GPS, of course, is its nonjudgemental nature. Heath rolls with the punches no matter how many bonehead turns I make. But even in his compensation for my mistakes he mocks me, pulling a fast one by, essentially, maintaining two sets of rules.  His jabs are subtle.

You see Heath has two routing modes that I don’t know what they call in Kansas where Garmins come from, but I call the two modes smart ass and dumb ass.

Smart ass mode is invoked whenever I make a wrong turn. “Recalculating… As soon as possible turn around and go back,” says Heath. Or he’ll say, “Recalculating,,, As soon as possible make a U-turn.” In smart ass mode, you see, Heath questions my judgement, undermining me in front of my children.

But Heath never second-guesses himself, because if he isn’t recalculating Heath never looks back. He doesn’t even appear to know there is a road behind him.  In this mode Heath is like an Italian Formula One driver who throws away his rearview mirror because what‘s behind him doesn’t matter. That’s dumb ass mode where Heath could backtrack half a mile saving half an hour but won’t ever do that. I first realized this in some small town when I got off the freeway for gas and — rather than put me right back on the highway a hundred yards from the pump — Heath guided me slowly through town before putting me back on the very same highway.

As the expression goes, familiarity breeds contempt. Ask Heath for a handful of distances, like how far it is to the nearest Mexican restaurant, and he’ll instantly spit out half a dozen places within a few miles. Not so fast: those distances are as the sombrero flies — un-routed. That 5.7 miles to Dos Perros in Durham, North Carolina could in fact be 10 miles or even 20. All you can know for sure is that it isn’t 5.7. Not even close.

GPS helps us eventually find places while, at the same time, putting us in our places. It’s a love-hate relationship, at least for me.