#6: RON TO THE RESCUE!
We're just getting started, kittens. How about the moment in The Deathly Hallows when Harry sees the Sword of Gryffindor at the bottom of a frozen lake? Harry figures that, to retrieve the sword, he has to demonstrate the Gryffindor traits, which, I assume, include foolhardiness and being impervious to hypothermia. So, he breaks the ice and dives in. As one might suspect, this doesn’t go well—though in fairness to Harry, it's because the Horcrux around his neck starts strangling him. Not an easy thing to predict.
And then, Potter gets lucky again! Ron chooses this exact moment to return to the gang after having abandoned them. And, of course, Ron has the good sense to immediately check the nearest frozen pond for any sign of his pal.