I cannot comment generally on why it seems such a hard thing to master, as I used to be under impression that it should be the basic skill and that everyone is capable of doing it with a bit of practice.
Perhaps the reason I cannot do it is because I associate it with porn movies, and apart from the obvious sex act the rest is just plain terrible acting (or am I watching wrong kind of porn).
Also if acting is required on WG's part then I must be a terrible punt, as I never feel a need to act in any sense, I do and behave the same as I do in my personal sex life, and talking dirty is not a part of it.
Sorry can't offer any better explanation, as this is the subject that I often wonder about .
Thank you for your insight, I always assume that a little bit of acting is required by a WG as sometimes in reality you aren't going to be attracted to a punter, still you have to convince and act as though you are to that punter. I don't see anything at all wrong with that, a checkout operator at Tesco's also has to act a bit when focusing on given good customer service.
You raise a very interesting point about porn which I will throw out there, has the rise and availability of internet pornography mean that WG are more influenced by that in recent years recognise the terrible acting and then cannot bear to think they might be giving that impression when dirty talking.
It seems to strike fear into many WG hearts. For example a very, very good regular of mine makes me turn the sound down to zero if we are watching a short clip of porn on my phone to get an idea about something. Now this WG is gold standard but even she will cringe and refuse me if I don't turn the sound down that is a very strong reaction to have.