In a famous passage Sartre discusses the behavior of the stereotypical French waiter. Waiters in France are expected to behave in a very specific way, they have a specific role in the play being enacted at the dinner. This role is to be as faceless and robotic as possible, as much an automaton as they can be (in contrast to the American waiter, for instance, who is expected to portray a generic friendliness). However anyone experiencing the French waiter’s behavior is quickly aware that it is put on, that behind it there is a person who would behave very differently if you met them after they clocked out for the day. And this immediate awareness of the real human being behind the automaton comes about precisely through the waiters over identification with the role, the exaggeratedness of their playing of it. Through a twist in our perception their apparent over identification with what is after all only a job role exposes the gap between the facade and the real person.
The converse of this is the British or American lawyer or chartered accountant, who through a touch of sarcasm and self deprecation here and there (the lawyer that occasionally tells lawyer jokes, for instance) lets you know that they aren’t a “generic” lawyer or accountant but “themselves as” a lawyer or accountant. Despite the appearance of not “fully” identifying as their job role, this mode of behavior betrays their real self-identification with the role and their enjoyment of the prestige and respect they feel it affords them. A correlate of this is that they find it far more difficult to “drop” that role in a situation where it’s inappropriate (for example, I’ve taken precisely that type of person, a CFO, to a Rancid concert and observed their discomfort at not being able to adapt to a situation where their “being a CFO” is entirely irrelevant).
This relates to people in 24/7 M/s or D/s relationships in a unique way. By virtue of the intent of the initial role adoption (as a Master/Dominant or slave/submissive) to be 24/7, i.e. to be “really” who and how they are, rather than playing a role for employement and dropping it the instant they “clock out” (or in this case are not “in public”), the “bad faith” that Sartre identifies the waiter as having avoided through exaggeration is inverted. The “slavelier than thou” slave or “domlier than thou” Master are the ones that betray a lack of self-identification with the role they are in, and since the claim is that that is who they are, they are in bad faith in the Sartrean sense. Conversely those that tend to understate their role, self-deprecate their ability in the role, are precisely playing “themselves as” a Master or slave, and as a result the self-identification is genuine and over time becomes more so. They are a Master/Dominant or slave/submissive in full good faith.
To some degree, then, anyone new to living in this manner is liable to be a bit more “over the top” than someone who has, over time, more fully identified with the role by making that role their own in their own way. But genuine self-identification is by no means an automatic thing that occurs over time, and as a result, as with the waiter or the lawyer examples, can be used as a rough guide as to how “genuine” a given person is in their claims as to who they are and how they live.