Commissar Draco
It's not what I meant. Certain real life aspects are hard (if not impossible) to recreate in a role-playing game. At the top of the list - anything that can be filed under "fear for your life", true selflessness, and realistic emotions.. Since your character is, for all intents and purposes, immortal, you'll bravely send him into the deepest dungeons and pit him against the most terrifying foes. The only emotions your character feels when looking at a towering dragon who can burn him to a crisp and swallow him whole are greed (loot!) and bloodlust (Imma gonna kill me some of that, I bet it gives tons of xp!). If a stranger asks you for a magic potion to heal his sick relative, both acts mean nothing to you - you know that you will never run out of potions and you don't give a shit about his stupid relative, who probably doesn't even exist in the game.
Geneforge had a cool moment when an NPC asked me to prove my beliefs by breaking a canister - a limited and very valuable resource that increases skills and abilities. Now that was something, but most games' design doesn't come close.
So, going back to swimming. Since it doesn't take much from you and you know damn well that your character won't drown, it really becomes a whimsical decision: do I feel like a psychopath today?