Chris Sullivan is a really cool guy. We actually have some mutual friends in common who went to college with him and they'd be super impressed with how incredibly awesome and fan friendly he is.
I mean, not only is he on This Is Us, but he was in Guardians of the Galaxy 2, so he could easily be super stuck up. I've seen it happen to tons of people once they get a little bit of success. Not so with Chris, though. We probably have at least ten pictures together by now and he's always great.