BOBBY: Don't you wish days like this could last forever?
ROBBIE: Well, if you believe in the theory of limited good, every good day we have is a bad day for someone else. So, if days like this did last forever, someone out there would be having a miserable life.
BOBBY: So, when I'm sad, it makes someone else happy?
ROBBIE: I'm sure people laugh at your misfortunes daily!