Weird English...

There is a phrase that I heard again yesterday, which reminded me how much I really hate it! I re-met a uni student who just returned from 8 months in Canada (it was strange because we met briefly in the first weeks I was here). The first thing he said was "long time, no see." What does that mean anyway? Why do people say that?? It sounds like cave-man speak, or at least like my students who can't speak English! My students simplify their sentences to two-word utterances like this: long time..... no see..... It's not that much more difficult to add a few words and say something more sophisticated, like, "It's nice to see you again," or, "Wow, it has been awhile since we last saw each other!"