Answer:
From "A Wad of Gum"- getting gum on her hair caused Serena to start yelling.
Explanation:
Naturally, most women values and cherish their hair hence the reason why the take adequate care to maintain it. For anything to happen to the hair makes them angry and feel sad.
In the case of Serena, if there should be a gum on her hair, it would make her to start yelling. This is because, the hair is going to be messed up by the gum.