I would think that Glinda would be hard in the Second Act, not as hard in the First one because she's always getting what she wanted, and in the second act her world comes crashing down on her.

I mean, Glinda befriended Elphaba because she felt guilty for what she had done to her in the past, and was trying to make up for she did in the past. As a reasult she actually cared about Elphie as a friend. But when Elphaba doesn't want to work with the Wizard, Glinda has to choose between fame or friends. She chose fame, and she has to live with that, but she gets adoration from the Ozians and feels wanted, but is unwillingly being controlled by Madame Morrible. And when Elphaba and Fiyero run away together, she's crushed and WILLINGLY suggest something that will later kill Nessarose, but she doesn't realize it...but at the end she makes up her at the end, but then she has to watch Elphaba 'die' and watch everyone rejoice about her death, while she has to mourn alone. Sounds rough doesn't it? Yessh it does

If only she had joined Elphaba in the first place...

yeah, life would be simpler if she DID join Elphaba....but then half the musical would change, and that would stink! (and then the Wizard of Oz would be different too)