Many years ago while eating my meal onboard a flight I dropped my paper napkin. As I watched it fall it got sucked to the wall of the plane. I pulled it away and let it go and it went right back to the wall. I called the flight attendant, showed her what was going on and she said "I don't think it's supposed to do that!". She notified the cockpit and the co-pilot came back...looked at the napkin and said "I don't think it's supposed to do that!" I appreciated that higher degree of expertise!