There may also be the possibility that the other person in the theater was making a joke. So, as a charitable person, were I in that situation, I would smile at the joke.

Of course, internally, I would make the more likely assumption that the person is an uneducated jackass. After all, he already spoke rather loudly during a movie at the theater, so I already know he's a jackass.

But since I am a charitable person, none of those thoughts would be outwardly expressed, and for all appearances, I would be smiling at a joke.