First let me say I have never been a Mariah fan. She always seemed to wear clothing that looked too small for her and she never looked comfortable. However, there are a few of her songs that I enjoyed.
Today my impression of Mariah is that she is very insecure but she has a lot of empathy and compassion. Her performance last night may not have been lip synced as I notice much of the audio out of sync.
Actually my theory is that her marriage and collaboration with Tommy Matolla did a number on her emotionally and she has been a little unbalanced since her subsequent nervous breakdown...