Why is Frank so sad about his future planning?

M:What do you think you’11 be doing in five years’time, Carrie?
W:I definitely won’t be working as a car park attendant. I want to become an opera singer. I hope I’11 be living in Milan. What about you, Frank?
M:Unless I pass my exams, I’11 probably serve the customers in the restaurant.
W:Come on. Don’t be so sad. Cheer up, Frank.