Cognitively drained, the uglier side of our nature begins to show through the cracks in the façade we usually present to others.
Fine's argument is that our outward demeanour and propriety are a "facade" behind which lurk our "real" selves . This might be thought to be just a scientifically-supported version of the commonsense notion that we are not as much in control of our better angels than we would like others to think.