Second, the actor has to surprise me. This is the most nebulous requirement, but it’s important. Except for really small parts that aren’t supposed to call attention to themselves (e.g., a bank teller who just cashes the hero’s checks), it’s not enough for actors to just seem real. Seeming real is a requirement, but a second requirement is that I can’t predict their every reaction before they have them. Think of how someone might react if his or her significant other ends the relationship. There are many, many truthful ways—ways that would seem like a human being reacting and not like a space alien behaving in some bizarre, unbelievable way.
