Mine is quite funny.
As a weak low level character, you meet your first bear. What to do?
Scream and hop into the closest river!
As a lvl-30 something, meeting 3 forsworns where the archer of them takes down your HP to almost nothing.
What to do? Jump in a river.
As RPG goes, this wasn't what I intended to do but really, those rivers or lakes can save your life.
I just had to confess that I'm a bad player, but a great swimmer!