The larynx, also known by some as an "Adam's apple", becomes more and more prominent during puberty. Because of this, characters with prominent Adam's apples are seen as more mature and attractive. It also gives their silhouette more of a sharp and angular look.
Spike Spiegel (from Cowboy Bebop) has his Adam's apple on full display as he wistfully looks to the skies.
Do any of the illustrations below have you all choked up?