Playing a round with gifs. :)
I was looking at this piece of footage recently (from 2.20 What Is...) and thought that the only time we really see Sam this happy and relaxed is in Dean's dream. Seems significant somehow.
Also, I adore this smile. His face lights up.
I'm sure this is deliberately made to look fake, or forced. Sam never seemed comfortable with Amelia's dad. Even at the end when they were sharing a "laugh". Or is that just me...