The Marthas
Quote 1
Siobhan: "She's creepy. What's wrong with her lips? It looks like she's got a disease or something." (21.17)
Siobhan, apparently, isn't mean to Melinda because other kids don't like her, but because she doesn't like the way Melinda looks. By talking about Melinda right in front of her, she shows that she doesn't think Melinda is worthy of any respect.