This afternoon a man called the business I work at:
Him: Hello, I'm calling (for/from) mumble mumble mumble youth charity organization?
Me: Excuse me, could you repeat that? Who are you calling for?
Him: I'm calling (for [from??]) mumble mumble charity mumble.
Me (in austere tones): I am sorry, but I believe you have the wrong number. This is a business, not a charity.
Him: Oh... I... um...
Me: Goodbye! *click*
Afterwards, it occurred to me that he was probably calling from the organization and not asking for it. I took it to be the former, not the latter. He probably thought such replies as mine only happened in movies and had his faith in the goodness of humanity shaken.
This illustrates the necessity for proper enunciation.