Understanding
They eye each other across the table with interest. Everyone else there is at least somewhat familiar to them; they are new to each other.
Charlie wonders how you survive for twelve years without feeling the sun on your back or the wind in your hair. He does not think hatred would sustain him so long, even without Dementors in the picture.
Sirius regards him with a mixture of incomprehension and envy. Incomprehension of a life so different from what he had even imagined having, envy of a freedom he can never begin to understand.
After the meeting, they brush against each other by accident in the doorway. They stop, and exchange looks for a long moment, their bodies pressed closer together than is strictly necessary, each seeing the spark of incomprehension in the other's eyes turn to something else.
Neither sleeps well that night.