The airspace in Switzerland is said to be the most complicated airspace in the world, but when you look at the overall chart of Europe, it is quite likely this is just a marketing statement:
Nevertheless, having flown with private pilots in many countries, here I am in the co-pilot’s seat and making a turn over Pfäffikon at the southern end of Lake Zurich, en route to ZRH. For light airplanes engaged in private aviation, there is a 20 minute window during the morning in which the approach must be made.