Cameron Crowe’s scripts are often filled with considerate details. This kind of specificity makes the characters authentic and engrossing. 

A less thoughtful writer would likely focus on Penny Lane’s beauty as the primary feature of her character. Here it’s her warmth and honest enthusiasm that make her someone who elicits our attention. Her “real interest” is especially powerful when contrasted with condescension and cold-shoulders that William (the protagonist) is met with in the beats prior to this moment. 

We care what happens to this girl because in a hostile and uncaring world, she naturally cares.