In Day One: Evening, Stevens continues to reflect on the definition of "dignity" as it relates to professional excellence. He argues that one of the most important aspects of professional dignity is the ability to inhabit the role of the butler no matter what happens. He illustrates this belief with two similes that contrast the "lesser butlers" against the "great butlers."
Lesser butlers will abandon their professional being for the private one at the least provocation. For such persons, being a butler is like playing some pantomime role; a small push, a slight stumble, and the façade will drop off to reveal the actor underneath. The great butlers […] wear their professionalism as a decent gentleman will wear his suit: he will not let ruffians or circumstance tear it off him in the public gaze; he will discard it when, and only when, he wills to do so, and this will invariably be when he is entirely alone.
First, Stevens says that lesser butlers treat their job like "some pantomime role," as if they were actors. Any mishap, he claims, will provoke bad butlers to "reveal the actor underneath"—in other words, to abandon their butler attitude and act as they would privately. Conversely, Stevens says, a great butler would never reveal his private self while in public. A second simile allows him to explain what he means: this kind of butler will "wear their professionalism as a decent gentleman will wear his suit." No provocation or metaphorical "ruffians" will rip the suit from him, because no decent man would go naked in public. In the same way, a butler cannot "take off" his professional attitude simply because of insults or extenuating circumstances.
Stevens continues the suit simile to make a claim that some readers might find strange: the best butlers will not "discard" their professional role until "entirely alone." This suggests that butlers cannot ever be themselves with their employers, employees, coworkers, and acquaintances, even in times of great personal need. Readers will see throughout the book that Stevens adheres to this rule strictly, to his detriment.
In her letter to Stevens, Miss Kenton references what seems to be a small event—Stevens's father pacing outside while looking at the ground—but is, in fact, as Stevens explains afterwards, the tip of an iceberg. An excerpt from Miss Kenton's letter in Day Two: Morning briefly mentions the pacing:
If this is a painful memory, forgive me. But I will never forget that time we both watched your father walking back and forth in front of the summerhouse, looking down at the ground as though he hoped to find some precious jewel he had dropped there.
Stevens explains how his father fell in front of Darlington and guests. As a result of this and other mistakes, Darlington asks Stevens to demote his own father. His father reacts emotionlessly, but later, Miss Kenton sees him retracing his steps over the pathway he had stumbled on, as if practicing or trying to discover where he tripped. She calls Stevens over so he can see.
There is a lot of significance in this scene. Two noteworthy things are Miss Kenton's involvement and the simile that Miss Kenton chose. Miss Kenton doesn't always like Stevens's father or his work, but she's taken enough notice of him to know that this behavior has significance. It seems she even knows why. She also knows Stevens should see his father pacing, if only because he so infrequently gets insight into Stevens senior's inner world. Kenton also remembers this event well enough to mention it in her letter to Stevens, which she wrote years later. Her simile, which makes Stevens senior's pacing into a search for a jewel, also illustrates that she understands what a crucial moment this is: the older Stevens searches for something precious, an ability or youth he once had but has since lost.