A boy meets a girl..

A boy meets a girl in the line of the school's cafeteria. The line was long, so they had a lot of time to spend with each other. He really likes this girl so he asks her out to the dinner the next weekend.
At the restaurant, the boy and the girl had to wait in a line much longer than the line at the cafeteria. They became closer from this, laughing about how often they spend their time waiting in lines. Finally they are seated and enjoy their meal.
A month later, the couple go to the school prom, ironically the boy had to wait in a 30 minutes in a line for the flowers, 45 minutes in a line for the tux, and an hour in the bathroom! Tired from all of this waiting in lines, he is excited to spend some time with the girl at the dance.
Many people go to this school, so the line to get into prom was long itself, which really didn't bother the couple, since they were so used to the long lines anyway, they made it fun.
Finally after all this time the couple are at the prom and begin dancing the night away. After a while, the two are very tired from dancing, and sit down for a little bit to take a break. "Could you go get us something to drink, please?" says the girl. The boy gets up, walks to the concession stand, and there was no punchline.