there's something to be said about wicked's opening and closing numbers both ending with a high cry of "WICKED" and while at the start of the show glinda is singing it with the ensemble, at the end she's silent on that final word. she's said her piece, she's told them the story and they're still crying out that elphaba is wicked, and this time glinda can't bring herself to join, too hurt to keep pretending.

instead, the last thing she sings is a reprise of for good, showing just how much elphaba did change her. she's not willing to join the crowds anymore.

also by not having glinda sing the last words, the narrative further isolates her from the rest of the world. she's truly and utterly alone.