I like mastery. It helps me to select something to do and gives a goal to work to. But stuff like this really takes away all pleasure:
What's the particular problem? 50 miles on US routes is fairly easy, two or three runs on either of the Boston routes, the two LA routes or San Fran peninsula should polish that off. Of course if you are referring to progress not registering (or vanishing) that has been an ongoing issue for quite a while and can usually be remedied by opening a support ticket.
But i don't want to keep making support tickets. I get to do that at work. Although Credit where credit is due: Dovetail is better at resolving tickets
For me it often shows 0 progress until the whole objective is fulfilled and then the bar gets all yellow.