Just a change in expressions. I don't mind the 'np', as I think it's as genuine as 'yw'.
I have my own bug, though. Instead of hello, people say "Hi, how are you?" and don't want a real answer. They expect the standard "Fine, thank you.", and then carry on. Give them a *real* answer, like "oh, I'm having a great day shopping, how is your day?", or "Well, my dog died yesterday and I'm real sad". This is often the response:
If ya don't wanna know, don't ask me! (and that's *my* old fuddy-duddyism) : D