She had more feelings than she knew what to do with, more emotions than her tranquil life permitted her to discharge. She had to invent sorrows and concoct dramas. She would stoop down to rejoice with a daffodil that had pushed a stone aside in its upward thrust, or would loosen a butterfuly from a spider web with wailings that brought her no sympathy from any listener. As if she cared for sympathy! She was capable emotionally of a woman's tragedies and, up to now, she had been unable to overtake any of these. Now, however, she loved and was not loved in return.
A succinct way to sum up the confusion of adolescence, and the melodrama in every momentary crisis. The process of emotional maturation can be painful and overwhelming at times.
Of course, I expect that boys go through this process too, but it's complicated by the fact that men traditionally were discouraged from crying or showing any other vulnerability. There's an early example of this in the book, where Cress tries to rescue a young boy in school, but Edwin doesn't want to be rescued by her and he doesn't want to be seen as a pathetic victim. In a later chapter, Cress's father John confesses to his wife about his own youthful attempt to find himself in high school; he tried out a gimmick of spitting to make people notice him, but eventually came to regret having made himself look foolish. Searching for your identity can often lead to humiliating mistakes that haunt you.
As for showing emotions, even today you still find people insisting that sensitive men are weak and wimpy. Or worse, castrated by political correctness. Extremes of any sort are bad, but there's a healthy middle road between macho stoicism and excessive blubbering over trifles. There's no harm in a man showing that he has a heart. Even Spock gave in to his half-human nature sometimes; even Sherlock Holmes let his mask drop when Watson was wounded in "The Three Garridebs."
I'm sure that men are every bit as emotionally complicated as women, no matter how much they pretend that they are shallow and simple creatures; they just mature at a different pace than we do, and are sometimes afraid of introspecting. I remember being surprised when I heard Neil Diamond's song "Shiloh" about his imaginary childhood friend, and his "I Am... I Said" speaking of an adult loneliness as well. Imagination is indeed the refuge of young misfits. It's probably what led me into writing fanfic at all.