Just as the natural inclination of snow is to melt in warm weather or freeze in the cold, now your character well enough to know what his natural inclination is to act when around friends, with family or with business colleagues.
And then, as the story develops, ask yourself if you can change the character’s natural inclination. The fun is to watch your character change. Unlike snow, humans evolve. And then ask yourself ‘If they change their natural inclination, is that change believable?’