Sam's friend Randy is the voice of reason. She's the one who not-so-gently reminds Sam that Jake Ryan doesn't know she exists. She's the one who offers a reality check when Sam's upset that her family didn't wish her happy birthday.
RANDY: Well what do you expect, a breakfast birthday party?
And she's the one who tells Sam how she can capitalize on their forgetfulness:
RANDY: Why don't you remind them? They'll feel some massive guilt, it could be highly profitable.
Seriously, why doesn't Sam take her up on that? Sam simply lets her family apologize and that's that. She could have at least gotten a nice gift card out of it.
After the dance, we don't see Randy again. Bye, Randy.