[derefr]

Eh. There are social signals that are important, and then there are ones that we should really be able to strip away once we've mutually acknowledged that we're "switching protocol" to a version of socializing that doesn't require it. Many things can be included in this, from saying "god bless you" when someone sneezes, to buying one another birthday presents. As long as you realize that you've already communicated the knowledge that the social signaling mechanism was supposed to convey, you can drop the signal itself.

Of course, this is for the nerds who tend to over-analyze social situations for fear of screwing them up; there are also the kind who just have no idea what is considered "normal" behavior in the first place, so they don't have enough information to even choose to obey or disobey social mores. In the latter case, I'd advise "critical people-watching" to figure that kind of thing out; your nerd will then likely transition to the over-analyzing type once they have this large, novel corpus to pattern-recognize over.