Now, I really need to beg your pardon - for switching to English.
When I was a TA at a university in the South back in the 90's, a professor ran out of chalk in the middle of a lecture and asked me to go to the front office to fetch a piece of chalk for him. Partly due to the professor's heavy Southern drawl, but more due to my being an unexperienced TA yet to learn my ways around in the classroom, I returned empty-handed.
"I am sorry, professor, but I could not find one," I said timidly.
Needless to say, the professor was dumbfounded. Being the typical Southern gen that he was, he struggled for a few long seconds to find the right words to say about the utter unbelievableness of the whole situation.
"Are you serious? You cannot find a piece of chalk in the entire building?" The professor finally managed to get out this much.
Now I was equally dumbfounded - if not more so.
"You asked me to get a piece of chalk? Not to find a fella by the name of Joe?" But too embarrassed to breathe a word, I asked these questions only in my mind, and then repeated the same questions in many a nightmarish dream for the next two years.