Why does Steve say he wants to open his shirt when miss O'Brien looks at him?

Steve expresses a desire to open his shirt when Miss O'Brien looks at him as a way to seek her attention and approval. This moment reflects his vulnerability and the intensity of his feelings towards her. It symbolizes a yearning for connection and an attempt to showcase himself in a more appealing light. Ultimately, it highlights the complex dynamics of attraction and self-presentation in his interactions with her.