Why is David being invited?

W: I really can’ t stand the way David controls the conversation all the time. If he’ s going to be at the Christmas party, I just won’ t come.
M: I’ m sorry you feel that way, but my mother insists that he come.

W: I hear there is a good Japanese restaurant nearby. Would you like to go there for lunch?
M: Yes, but it’s my treat this time.