This might be hard to believe given that The Phantom of the Opera is a musical that is almost entirely sung, but few leading actors put any emotional weight into their vocals, preferring to rely on a combination of their skilled visual performances and the inherent beauty in the lyrics/music to carry the character's journey. This isn't hard, since the script packs a slew of emotions for our leading triangle, but one of the best things about Phantom's 25th anniversary production is that Hadley, Sierra and Ramin put so much emotion into their singing that you could listen to them with your eyes closed and still understand what each character's going through internally.
To see what I mean (and feel free to experience this with your eyes shut), here's the song "Wandering Child" sung by Gerard Butler and Emmy Rossum in the 2004 film adaptation: