T'Pol is a young, emotionally confused Vulcan who has no real experience in her own culture's history or the galaxy at large. She has jilted her fiance and betrayed her government because the humans on Enterprise make her feel important. Her only true assets are on her chest.
She believes that demeaning and insulting people is prudent diplomatic behavior. She once derided a human by calling him an "impulsive carnivore" after he ate a breadstick. Later she showed a massive lack of concern for her fellow crewmates when she used narcotic minerals (to Vulcans, at least) intended to help shield the ship to get high. These were the same materials that the crew weren't using because of their concern for her well being.
She was the first officer and science officer of the USS Enterprise.