Geralt is kind but he doesn't go around looking to fix the world's wrongs. He knows better. Thing is, he has a pretty strong set of morals so when something pushes his boundaries he can't help but get involved - despite what his common sense and life experiences tell him. He isn't greedy but he certainly doesn't appreciate people trying to swindle him out of his reward - it's his livelihood and he's mostly poor. He tends to feel sorry for himself quite often and gets bitterly sarcastic in those moments. He usually doesn't resort to monosyllabic responses like the game version; not to say he's outrageously chatty but he's very well-spoken and can be very witty, in a dry-as-a-desert sort of way.