Behavior modification

First off, this isn't sparked by anything in the office. We're pretty mellow around here.

Praise in public, correct in private

Simple words, yet we've all run into violations of it. Such as the following from a hypothetical manager:
We've been having some problems lately with people using their cell-phones excessively during working hours. We need to try and do better.
Which everyone knows that We actually means [person], and manager is too gutless to talk to [person] about their excessive cell-phone use. Instead preferring to issue a semi-anonymous dictate from on high. In my opinion, this is probably the most common manifestation of failing to follow this. Less common are the outright public criticisms, as most people realize that isn't a winning strategy (unless the manger intends to rule by fear, which some do).

That said, there are some circumstances in which a public correction is called for. Such as when the behavior requiring correction was highly public, highly sensitive in some way, or if failure to address the problem in public will significantly impact morale. In a sense, this is a failure on the part of the errant party to keep their transgressions reasonably private. Excessive local-call abuse? Pretty private, worthy of a mangerial talk in person. Surfing porn during working hours? Pretty private until you get caught, then it gets public real fast (at least in America).

If your transgression was big enough that the manager has to save face, you will not get a private rebuke.

As I said, this office is pretty mellow and this hasn't come up. But I still hear stories of other places.