Do you know non-technical people that can do this well and consistently? How do they do it?
Everyone should try to be friendly and professional, and clearly being rude won't win you any favors, but you shouldn't get moved to the front of the line because you stopped by to talk about last nights game or how my kids are doing. That's not a solution that can scale.
My have tremendous fondness for people that work in Corporate IT. I've worked there in the lowest levels, managed them, protected them, fought for them, and ultimately have seen that the larger system at play works against them. I believe they are usually the smartest, hardest-working, most creative, most driven people in the company.
I should have set the context of my comments for those working within dysfunctional companies where IT is at the bottom of the pecking order. In my experience, this is when the need for strong relationships will go the farthest.
If things in an IT org are great, professionalism is key. Otherwise, I stand by the idea that being nice is more important than being clear.