If your character has an abversion towards steel weaponry, and a new steel weapon comes out, then tough luck!
Through roleplaying (pen and paper) I discovered that many people are unrealistic in their character creation, for example the Paladin, a paragon of holiness and justice, yet what about weaknesses, is he completely arrogant, ending him in trouble, does he question his faith?
Not many people create a weakness for their characters, I liked the way that the MB selection screen had positive and negative traits, and games like Fallout do too (A pity they mean nothing in MB). No one is perfect, thus no character can be either.
I have long modeled my characters with rather large flaws, whether it is a personality flaw, or something more extreme. An example is my latest D&D character, a powerful master of Evocation, that is too arrogant for his own good, and refuses to heed any advice, making many enemies. Or my first character, a simple Rogue who was a skilled thief, but has no patience and is deeply hurt by the ruthless slaughter of her friends.
My first PS character (Adeli) was merely a vessel for me to familiarise myself with Hydlaa... RP was not a factor in her life, as I just wanted to experience things for myself. My current character (Tyralus) is how I wish to be known in the game, and I spend most of time in-character, and as such he needed a background.
I modeled him after my first ever D&D character, an intelligent, skilled, agile and witty thief... then changed some things, he too lost his friends that were like family... Tyralus\' family was killed by a mage, and he bears a cold hatred for those of the Arcane. To make matters worse, he is unevenly matched against spellcasters due to his deathly fear of magic.
Because of this, Tyralus will probably never use magic, unless he does it to desensitise himself, in order to overcome his fear and get revenge. He is often taken by blind hatred, and will flee from battle when a wizard is involved, he also lacks the ability to trust again.
I agree with Golbez that hipocrisy ruins the RP factor, which I see as very important. Sorry for the essay.