Dear anita and Peter:
Thank you for your kindness in your reply.
Dear Peter:
This is the second time I have met with this lecturer, and she treated me in almost the same manner for both meetings. So I think that it may not be a one-off incident that put her in a bad mood.
I find your rule of charity helpful for me to think about such incidents. Using this rule lead me to think that her behaviour can be due to a mismatch between our personality and not because she is out to make my life difficult or I am too imperfect to her.
Thanks again!