I'm not claiming to be an expert on the matter, but I have a lot to say on it. (Shocker! Someone on the internet with an opinion! (: )

I believe you may have hit on the crux of the thing, if by accident. From my own perspective, it seems that the proper greeting is the most important matter - it is more important than the work you have in mind. There is no "better things to do", because the relation and respect of the thing leads to those work things.

Maybe giving an few examples would make some kind of sense.

Example 1:

"I am in a rush I can't follow formalities!"

"I don't deal with people who rush."

Example 2:

Imagine someone who pees on the floor in your house because they exclaim that, "It is too much effort to go to the bathroom, access the toilet, and clean up afterward!" Would you invite that person back into your house after that? Would you have a desire to work with them, and keep a beneficial relationship going with them? Maybe? Depending on who they are, or what the circumstance is, but for most circumstances, sensible people would answer with a very firm, "No. Of course not!" because what they did is gross and rude. What they did is plainly disrespectful - it is a disrespect of laziness and indifference. They do solely what benefits themselves and have no interest in how that may impact you. It is contemptuous.

In my mind, a working relationship, is the result of having a relationship with that person. It is something that advances from having a bond with that person. You offer them respect, they return it, and in doing so you can be assured that they aren't a crazy person, or are going to do something that puts you in a terrible spot. The fruit of that respect, that bond, is a relationship that permits you to work with them.