When Did the Reply to "Thank You" Become "No Problem"?

Have you been treated to "no problem" as the new reply to "thank you"?  I encounter this every day from young waiters/waitresses, store clerks, parking attendants, and a whole host of others working  in service industries.  My reply to that illogical response is "I know it's no problem for you... BECAUSE THAT'S YOUR JOB"!  Would you have told me it was a problem if I had interrupted your cell phone conversation? How about that comic book you were reading? Maybe if you were playing Words With Friends on your iPhone. Perhaps if you were in the back working on a cure for cancer. No?  If none that is what I have taken you away from, then the reply to my acknowledgment should be the tried and true "you're welcome".  Try it out on your next customer.  It's the right thing to do.