This is one of the most oft-cited examples of subtext in a movie, but we’ll repeat it now because it’s a great example of role-playing subtext. 

Sometimes when a topic of conversation gets a little too salacious or uncomfortable, a character might take the heat off themselves by playing a role or pretending to be someone else. 

When Phyllis realizes that Neff is coming onto her, she polices him, but he plays right along. If they’re not themselves, they don’t have to take responsibility for their emotions or for the wrong turn they’re taking.