It's hurtful to back out on your prom date.
David promised Cindy he would take her to the prom when he couldn;t get concert tickets for the same night.
David wants to have a good time on prom night.
David thanks his friends but unless Cindy could go too David declines the offer.
David's friends surprise him with an extra concert ticket on prom night and David decides to go to the concert instead.
Cindy  is happy, David is happy and the girls admire him.
Cindy is no longer David's friend and no girls from school will date him.