Where I live, directions to place you've never been usually comes with the caveat "You can't miss it." That phrase is a real downer, because when you hear it, you're doomed to become lost. Then when I find the place I'm looking for, I always wonder why they didn't tell me about the big sign that would have made it all clear. Why can't people give directions that someone can follow?
The reason we find it hard to give good directions is because of the "curse of knowledge", a psychological quirk whereby, once we have learnt something, we find it hard to appreciate how the world looks to someone who doesn't know it yet. We don’t just want people to walk a mile in our shoes, we assume they already know the route. Once we know the way to a place we don't need directions, and descriptions like "its the left about halfway along" or "the one with the little red door" seem to make full and complete sense.
But if you've never been to a place before, you need more than a description of a place; you need an exact definition, or a precise formula for finding it. The curse of knowledge is the reason why, when I had to search for a friend's tent in a field, their advice of "it's the blue one" seemed perfectly sensible to them and was completely useless for me, as I stood there staring blankly at hundreds of blue tents.