One of the main things we learn in these types of games is to hit the ball within the lines. If we do, we can gain a point. If we don't, we automatically lose a point or forfeit our turn at whacking the ball. This is not the game of Marbles, where the marble can shoot past the boundary. It is also not the same as Christian reproving or rebuking, which are correct, appropriate forehand moves.
Vicious forehands can include false accusations and curses, and other forms of verbal abuse.
Aggressive behavior can, of course, mean really losing all vestiges of civilized behavior, and running across the court to attack our neighbor. However, beating someone up with 'just words' is still beating someone up. When we are not loving our brother and sister enough to stay within the boundaries, getting the upper hand has become too important to us. Even protecting ourselves from something can become too important, when it is motivated by insecurity and fear. Unproductive and unnecessary conflicts are about power-struggles, egos, and fear.