Sam noticed Dean grin broadly as they drove slowly down the highway, due to traffic. Sam couldn't understand why he was grinning. They had been almost sitting for ten minutes now. Sam was already in a grouchy mood, and Dean's odd happiness was annoying him.
"Why are you grinning? We're stuck in traffic!" Sam finally asked. Dean turned to him still with that infuriating grin on his face.
"I'm talking to the kids in the car in the other lane." He turned and waved laughing. Sam looked at his brother incredulously.
"What?" Sam continued to stare confused as his brother laughed and waved again.
"Look! They're right beside us now!" Dean smacking Sam in the shoulder excitedly. Sam leaned across and saw two excited teenage girls who were laughing hysterically and waving back. He could just barely hear one girl say: "Look! There's another one!"
The other one replied, "Oh my god! They're both so hot!" Sam smiled as he realized that the girls didn't know that their conversation could be heard. Dean began laughing his head off.
One girl began to turn bright red as she quickly grabbed her friend.
"Crap! I think the heard us!" She practically screamed. The other girl was quickly silenced.
"Well-shut up then," she muttered embarrassed. Dean began to choke on his laughter.
Ignoring her friend's advice, the girl who was supposed to shut up, grabbed paper and pen and quickly wrote a note. She held it against the window. It read:
"SO-What's up with you?"
Dean and Sam laughed as they saw she was trying to change the subject. Because they had no paper and before Sam could stop him, Dean leaned out his window and yelled: "Nothing much! How about you?"
They girls giggled in response. Sam turned to Dean grinning.
"No wonder you were laughing."