Gee, what were you doing, referring to the fish by its scientific name?
Of course every MSP and client is different in their expectations about some things. Before we go out we review order requirements, payment method and what 'trademarks' of the restaurant we need to observe. So for one client it is really important whether or not the server mentioned and described the sauces. For another it is really important whether somebody held open the inside door for you. Still another expects their staff to provide you with a black napkin if you are wearing dark pants or skirt and white napkin otherwise. Aside from the quirks, though, the timings, names/descriptions, 'atmosphere' and cleanliness are standard. This makes the on-site experience quite easy to do.
The report writing can be a PITA because one MSP wants you to refer to yourself only as the Analyst, while another wants you to be non specific about gender so you can use "I" and "my companion". One MSP wants you to refer to staff by name throughout your report while another wants you to use gender anonymous referals to staff as "the employee", "our server", etc. I have my file cards of client standards for report writing because I don't like my knuckles rapped because I referred to Annabelle as "our server" throughout the report. Makes for a rather schizophrenic writing exercise sometimes.