You may recall my pet peeve with "no problem." Typically, some half-unshaven twentysomething hooked up to a music player uses the phrase to respond to a customer complaint, as if to say that he will tolerate the effrontery of interrupting his mp3 listening to handle a refund or a replacement request. Right, I was so worried about your entertainment at work, kid!
Yet there is a right way to use of the phrase and I came across it this week. On my way to work I thought I inadvertently inconvenienced a young woman and immediately offered an apology, to which she replied with a smile, "No problem." Exactly!
I had wronged her and she was being gracious, offering that it was no problem to her, speaking purely out of courtesy. In French, de rien (it's nothing) is offered, although usually it's in response to merci (thank you).
The sentiment is similar. I am really in your debt, but you offer graciously to relieve me of the burden by saying it was nothing, though we both know it was something.