What is the mood in So B It?

The mood in So B It is one of regret, sadness, and longing for a lost love. The song is about a person who is reminiscing about a past relationship and how things could have been different if they had made different choices. The lyrics express a sense of regret and sadness, as the singer reflects on the mistakes they made and the opportunities they missed. The mood of the song is also one of longing, as the singer expresses their desire to be back with their lost love and to have a second chance.