AKA "The best place to stand when collecting your luggage at the airport carousel".
Imagine the situation: You're at an airport, you're waiting for your luggage to come off the plane and you're standing by the carousel. You can't remember what your suitcases/bags look like as the Mrs/your travelling companion is looking after the kids/is otherwise indisposed. Where is the best place to stand in order to (a) retrieve all your luggage, and (b) minimise the amount of luggage you have to look at in order to decide if a particular bag/suitcase is yours or not?
The answer is as obvious as it is simple. You apply "Human Grepping" (a real life version of the unix "grep" utility with which it is possible to filter text files, printing out only the lines which contain matches) to the problem, ie. you stand at the point closest to the place where the luggage comes out onto the conveyer belt, but furthest away in terms of how far your luggage has to travel in order to get to you - in other words, you let all luggage complete at least one complete circuit of the carousel.
By doing this, you apply a filter to all of the luggage coming off the plane; since the carousel is crowded by other occupants of your flight, they perform the filtering operation for you by removing their own luggage from that on display. When a bag gets to you, the probability that it is your bag is high, whereas if you stand just in front of the place where the luggage comes onto the carousel you have to check every bag eith a vastly lower probability that the bag going past is yours.
It works amazingly well too. Try it next time you're on holiday, and you'll see what I mean! 8)