Captain's Log. Stardate 13th April 2013. One of the curious customs of the Cuadrilleans, and, for all I know, of the Kling-Ons in general (but my data sample is limited to Cuadrilleans on this particular subject), is that of greeting people with a "goodbye" instead of "hello." I found this very disorienting at first. Picture yourself walking along the street. You meet someone you are well acquainted with. You turn to them and say in their language, "hello," or "hi." Their response: "goodbye." And on they walk.
Well, a sensitive soul might think that this is a rather untactful way of getting rid of someone one is in no humor to exchange pleasantries with. After all, what does one answer to "goodbye"? Certainly not some small talk about the weather. There is, in fact, very little EXCEPT goodbye that is an appropriate response to goodbye. So when someone greets you with "goodbye," this not only dispenses with any pretense whatsoever to enter into small talk with you; it also protects the greeter, preemptively, from any verbal advances you might make toward them. What if you were overcome, for instance, with a gush of sympathy or curiosity about how said person was faring? Confronted with "goodbye," it would take an impressive amount of determination to proceed with a conversation.
Now, the advantage of this greeting convention is that once you get used to it, there is absolutely no awkwardness in walking by colleagues and acquaintances with a matter-of-fact "goodbye" and getting on with your business. Plus, you don't waste valuable time talking about the weather. Not to mention the fact that once you get to know the Cuadrillean character, you realize that this apparently cold and impersonal greeting is compatible, in his case, with an abundance of goodwill.