When someone is picking on theSlytherin, the Gryffindor stands up and tells the person to back off, and guides the Slytherin away from the fight.

When the Gryffindor is all sad and depressed, the Ravenclaw brings them a warm drink, and sits with them as they talk about what's going on.

When the Ravenclaw is picked on for not having the highest marks, the Hufflepuffreminds them there are different types of intelligence, and paper doesn't prove anything.

When the Hufflepuff is sitting on the sidelines watching the others play, theSlytherin is the one to jog over to tell them to get their butts in gear because they are playing on their team, and together they are gonna beat Gryffindor and Ravenclaw.