This is a worthy discussion of glassy water and losing situational awareness but nobody has yet mentioned Kennedy's loosing everything on his way to Martha's vinyard with two pax on board. He had no instrument rating; conditions over the water were getting dangerous, horizon ref had gone.
Which side is up? how can you tell?
The complete opposite to the amazing viz in your photos of that glassy water surface, promising clarity, no wind, no ripples, no boats....and situational awareness, relying on what you can see (the bottom of the lake) - oops!
and responding to Down West -
Over Scapa Flow, during the war, he describes how his old man was surprised that the other pilot was flying so close to the surface! "he grabbed the stick, only to find it loose - they both thought the other was flying the a/c"
Reminded me of the story about a tutor tandem 2 seat training glider, where the instructor had the evil habit of testing his student's composure by saying "Well, you are flying so well I don't need this any more!" and he would toss his control stick over the side.
Until a savvy student in the front of the Tutor replied "Well, I guess I don't need this any more either!" and tossed HIS stick over the side as well...
Needless to say the student had only tossed over a spare.. remarks by the instructor from the open cockpit could be clearly heard by all the happy spectators on the airfield....
(humble apologies for thread creep....)