When No Problem Makes No Sense

Over the next week, pay close attention to what others say when ...

* You thank them for something or ...
* A person in the service industry responds to a routine request you make.

Using just these two simple and common situations, I'm curious to compare how many times you hear the phrase "no problem" over the next week vs. how often I do. When exactly did "no problem" replace "you're welcome" in the common parlance? In your view, is "no problem" more likely to be used by one generation vs. another? If you answered yes, which generation do you think is more fond of this ubiquitous modern coinage - baby boomers, Gen X, millennials, the iGeneration?

I'm usually neutral when someone uses this phrase in either of the situations I asked about above. At the same time, I am often struck by how inappropriate the same phrase can be in other situations. So, pay close attention to those other situations as well over this next week. Then let's compare examples of when "no problem" makes no sense.