3. Terry Gannon often addresses Tara by name; in turn Tara often directs to "Johnny;" Johnny in turn often says "Terrance." (i.e.like swordance said above). I've noticed it and think it's funny but also kind of cool.
ETA: I just realized that my #3 ^^^ is also, in a way, another Rule of Three. If your mind goes off on tangents, like mine does.