well OBVIOUSLY i get that too. 'grin]
i've had some right old cases, where you could kinda tell (as could ed) that the people were a bit vulnerable really and needed to vent. you really wouldn't think that people (a minister's wife, no less) could get to wound up about my accidentally revealing that Ross is the father of Rachel's baby.
so - polite, prompt, conciliatory the only way to go, at which point they, without exception, fold and apologise for being a bit nobbish at the start. it's just a part of the job, i quite like the challenge of bringing people in, iykwim? (and am not afraid to make plain old hands up apology if i'd made an error).