Argentine Tango is danced counterclockwise around the outside of the dance floor (the "line of dance") and dance "traffic" often segregates into a number of "lanes"; cutting across the middle of the floor is frowned upon. In general, the middle of the floor is where one finds either beginners who lack floor navigation skills or people who are performing "showy" figures or patterns that take up more dance floor space. It is acceptable to stop briefly in the line of dance to perform stationary figures, as long as the other dancers are not unduly impeded.
The school of thought about this is, if there is open space in front, there are likely people waiting behind. Dancers are expected to respect the other couples on the floor; colliding or even crowding another couple, or stepping on others' feet is to be avoided strenuously. It is considered rude; in addition to possible physical harm rendered, it can be disruptive to a couple's musicality.
