conversing with experts

As a rule of thumb, when conversing with experts avoid dealing with their area of speciality. For example, don't try and talk to a star wars nerd about star wars. They will tell you that Han Solo shot first in the original version. Subsequently it was changed to show him to be more honourable. How the hell can I be expected to notice and remember this crap? Therefore I would avoid such a conversation in the first place.

At the other end of the spectrum you may need avoid an area of specialisation so that you do not shame the person you are talking to. For example, don't talk about toilets to janitors. Sure they must know a lot about commodes and turds but surely they might have other things to talk about too?

I was waiting for the lift so that I could make my escape for a long weekend and the janitor was waiting there too. He's a pleasant guy always smiling and cheerful and we were making small talk to bide the time. He asked if my office was closed on monday and I said yes and he said that was good because he was not working on monday so it would be not be cleaned. After a moment of reflection he complimented us for being a clean floor unlike the 27th floor. He shook his head in disgust when I ventured to ask if the 27th floor was dirty. He shook his head again to emphasize how filthy and unhyigienic they were. So that was his expert opinion and as deputy fire warden of the 22nd floor, I respect that. Stupid, unidimensional janitor.