I was reminded over the weekend of the importance of knowing where you're going. Twice in the same meet, runners went off course, wrecking their chances for winning.
I saw one case (last year) when a course official actually directed runners the wrong direction, but it's usually the case that there is a turn on a course somewhere with no official, and one or more runners go the wrong way.
Yesterday, in the first race of the day, there was one runner that was well in front of the others. Behind him was a sizeable pack, then a string of several others extending back from there. Just before the 2-mile point, the course takes a 90-degree right-turn. The leader, then the pack, then several of the others continued straight. The runner who was in about 25th place (one of the boys I coach) had listened all week when we had talked about the course, then had gone over it along with his teammates with a map in hand during his warmup. Even when the runner a few feet in front of him went the wrong way, he knew to turn, so he did. He ended up winning the race. Yes, knowing where you're going is part of the sport.
Later, on the final race of the day, another runner made a brief foray in the wrong direction. He was very close to the front at the time, but even though he only went off course for 2 or 3 seconds, it was apparently distracting enough to wreck his race: he finished somewhere above 20th place.
In today's age, you can usually find a course map on-line somewhere, so check it out and know where you're going!