Expression

n  The girl is mad, her mouth looks tight and her face pinched.

n  The guy is discouraged, his mouth droops, and he hangs his head, making it  hard to see his eyes.

When the girl talks, she lifts her eyebrows and keeps her mouth drawn tight.

n  The guy is bewildered, his mouth is twisted and he looks sideways, as she scolds him his face actually seems to fall, his entire face relaxes, and he looks away.

n   

n  They are interrupted, and the man is obviously irritated, he pinches his mouth, but attempts to smile. 

The girl's expression shows relief, she relaxes and smiles a real smile, using her eyes.