In response to bigracket1's reply:
Yeah, that's frustrating. I got trapped once on top of a mesa where the trail was faint to invisible. I spent two hours going back and forth looking for the way down (which had also been the way up), but just couldn't find it. The trail had been marked with very small and infrequent cairns, but critters had scattered them in the meantime. It was one of the few times I intentionally went bushwhacking to be ensured of crossing the trail. The whole time I knew almost exactly where I was, I just couldn't pick up the next turn. I didn't fully appreciate how anxious I had become until I felt the relief at finding it.
Another time I was temporarily misguided by an animal track that ran almost parallel to (but lower) than a rarely-travelled trail I meant to follow. After several fruitless attempts to locate the intersection, one of the best decisions I ever made was to set up camp and call it day. Everything was fine in the morning, and I found the trail in about 10 minutes.