Despite their differences, Abby is Beth's best friend. Beth can be considered a foil to Kevin; whereas he is impulsive and anti-authoritarian, Beth is cautious and apprehensive about breaking rules. She has good intentions but can be overly trusting of other characters.
Although they have different personalities, Abby is Beth's closest companion.  Beth contrasts with Kevin, who is impulsive and rebellious, while Beth is cautious and hesitant to break the rules. Despite her good intentions, she tends to be too trusting of others.