I think people are over reacting with her reaction.
I have the exact same look every time someone is giving a speech.
I don't feel the need to smile ear to ear even if I like the person speaking.
She probably hasn't had a PR person talk to her regarding her facial expressions at award shows.
People take the simplest of facial expressions and make a big deal out of it.
I'm sure by next time she'll have her fake smile ready.
at the Swifties taking this seriously, we have no idea why she had that look but it was funny/perfect timing.