This department deals with the oddities or characteristics that are uniquely Revit.
First up is the notion of "clicking in empty space". This is required to finish a dimensioning task or when you are done using the text tool. This simple task yields a considerable bit of confusion for a lot of new users. Once mastered we easily move on but it seems to be a very foreign concept and I get all kinds of looks when I begin to explain this technique.
All Revit is asking us to do is click somewhere, anywhere...as long as nothing is under the point of our cursor. Revit interprets this as "I'm done thanks!". It really isn't an unreasonable request, Revit just wants us to avoid picking another element so we can finish up.
This technique is also used to reset the Match, Trim/Extend, Align and other tools. We need to master it and it is easy...but it is definitely a Reviteristic.