This one must have happened early (when I was 5 or 6), but after a simple raft of logs had been constructed by some of my visiting cousins, there was a move to make a "real" raft to swim off of.  The pond was deep in the middle, but very muddy around all the edges, so a good raft really makes it quite a bit more fun.  Anyhow, real lumber and a couple thick styrofoam insulation panels were purchased and Dad slapped it together with help from some of my older cousins.   It was a great hit, and there were a lot of cousins visiting at that time.   I was the youngest of them all though -- next in age came Nansi, who I was insanely jealous of (because she could swim in deep water while I hadn't mastered the art of treading-water/staying-afloat).   So for me, the raft was doubly exciting.  I would be able to push off from the muddy bank of the pond and clutch the edge of the raft when it was drifing in close and then I could pull myself up on it and be part of the action.  The "action" soon became a really fun game of try to tip the raft over by everyone standing on one side.  Initially I was smart enough to *not* follow everyone over to that side, but rather stay on the other side until the raft tipped enough that they all fell off and I managed to stay on through one or two of those and I thought I was the cat's meow.  But then Nansi said "Why don't you come down here on the other end with us?" and my answer of "I can't swim though" was answered by her with a dismissive "So?"   That was enough.  There was no way I was going to let her embarrass me that way in front of everyone, so when everyone climbed up on the raft with us the next time, I went down to the same end with everyone else.   And of course I fell in the water and sunk.   I remember looking up at the water line and feeling as helpless as I've ever felt before or since.   I was flailing madly in all directions, but it wasn't helping at all.  I remember so clearly that I don't think I ever closed my eyes.  The memory of looking up and seeing that water line recede to 1 foot away, then 2, then 3, then 4, then 5  is still so clear I sometimes wonder if I've confused it with footage from some movie or tv show (but I really think not).  At what seemed like 5 or 6 feet away, a big shape splashed into view and my Dad came and pulled me out.   I remember coughing and retching and being so totally exhausted by the experience.   I sure tried to blame everything on Nansi, but it was at least several decades later before I came close to learning (and really understanding) the lesson from that one.   Where safety is concerned, pride has no place at all.