You can watch the intermediate and advanced guys fly a certain plane and tell there is a 15mph cross wind, then you go over and watch the top FAI guys fly the same design in the same wind and you wonder if the wind is even blowing.
How very true.
When I was flying in the Standard Class in the UK, even in the days of heavier loaded smaller 60-sized models, I always wondered how the better flyers always contrived to have the wind drop away to nothing just in time for their flights.