It's bad to not pay someone back.
Christian's crush, Lila, has asked him out on a date, but he is broke and can't afford dinner.
Christian wants to have dinner with Lila.
Christian borrows his uncle's rent money and pays it back when he says he will.
Christian borrows money from his uncle with the promise to pay him back before rent is due, but doesn't.
Christian and Lila were able to go on their date, and Christian's uncle is able to pay his rent on time.
Christian's uncle is late on rent and forced to pay a late fee.