You want to hear a good one I recently tried to fly one of my four stroke airplanes after not being able to buy 20/20 fuel for my ys engine. been using 2 stroke planes. I forgot when fueling the 4 stroke to disconnect the vent tube from the the one way valve connected to the engine. Ys engines use a pressurized fuel tank system. well I pumped fuel into the tank and the pressure in the tank kept building and building until finally the fuel filler hose popped off. The tank of fuel immediatly started spraying under pressure everywhere in my mouth up my nose all over my glasses in the eyes and all over my hair and clothes. I am now good for another year at least.