What was Claudia thinking about before it became clear that Maureen was not going to treat her to ice cream?

When Claudia realizes that Maureen is not going to treat her, she attempts to conceal the fact that she “fully expected Maureen to buy [her and her sister] some ice cream, that for the past 120 seconds [she] had been selecting the flavor, that [she] had begun to like Maureen, and that neither [Claudia nor Frieda] had a penny.”