Why was it so important to Gatsby that
Daisy like his party?
It's important to Gatsby that Daisy accept
him as an equal in her "old money" culture.
Gatsby wants to be a celebrity in Daisy's eyes
and in the eyes of the world; that will make
her fall in love with him.
Gatsby likes to host parties. If they're going
to be together, it's very important that they
have a love of parties in common.
Gatsby is generally an insecure person who
wants everyone to like and admire him. It's
natural that he should seek her approval.